Whenever anyone finds out that I'm a quad pilot, their first response is usually something along the lines of 'that's cool' or a question about range, maximum altitude or any other technical specification, something that for any good pilot who knows their quad's limits will be easy to answer. As they hear more about it, though, they will usually want to start buying and flying their own quads (or ask to borrow mine, which is fine with me as long as I can make sure they're flying safely and I get it back in one piece at the end), and ask how best they can get started. This is a much more difficult question to answer, but I'm going to try to put it on (virtual) paper o help any new pilots there.
The first thing to consider is what kind of quad you want to fly. At first, back when I started in December 2014, I didn't even know that there was anything beyond the realm of toy-grade quads. To me, the Parrot AR drone was my ultimate aspiration. If you're like me, then you fall into category 1. If you know you want to fly aerial photography/videography platforms, then you fall into category 2, and if you know you want to race/freestyle acro, then you fall into category 3. Obviously these categories are arbitrary, but they should make it easier to get you the best advice possible.
One final thing to say before I start going into detail is that this is my opinion and may very well differ from the opinions of other pilots.
Category one is where most people, at least in my experience, start. You know that you want to fly something (maybe you've flown a family member's quad, or you've seen some videos online), but you don't know what type of quad will best suit your flying style. That's absolutely fine, and this gives you the most flexibility in your starting point.
I always recommend getting your hands on a real quad first, my recommendation being the Hubsan X4 H107 C. This is a super hard-wearing little quad with a camera, an abundance of spare parts, good resistance to the wind and a good range (well, that being said, the main reason I have never run out of range on this quad is because it's so small that by the time it's out of range, I wouldn't be able to see it anymore so never tend to go that far out with it). The reason I recommend going down this route is because I know it works: I started with a Hubsan X4 H107 C, and it's what really got me hooked.
Once you have the transmitter in your hand, you can learn the controls and build up confidence, then really start to experiment to find your flying style; do you tend to want to get the best video possible? Are you trying to pull off the most difficult stunts you can? Are you just cruising around the field? Once you know how you fly, you know what kind of route you ahould take. If you chose the first option, then maybe a camera drone with a gimbal and GPS is best for you. If you chose the secod option, then you probably want a freestyle quad or racer (both of which should be capable of running Betaflight, Emuflight or similar if you want to be able to tweak the settings and rates to how you like them). If you chose the third option, then you're not really restricted to what kind of quad you want, but speaking from experience, cruising is much more fun in FPV. Perhaps look into a 7 inch freestyle quad: the larger props will be more efficient and give you better flight times. Obviously this isn't definite: your tastes and ability will most likely change over time, and you may find that you end up with a fleet of racers and a fleet of videography drones. If so, then lucky you!
Another way that lots of people recomend (especially in the racing and freestyle communities) is to start on a simulator (or, as they are usually called on online forums, sims). This way you can get your head around the controls and when you crash (it's inevitable, even the best pilots in the world will crash from time to time), you can just click a button and you're back up in the air. A disadvantage of simulators is that to get te best experience, you really need a proper transmitter (think FSi6 as a minimum) to hook up to your computer, which you will probably want to upgrade later on if you get seriously into the hobby. You could use a bluetooth controller or a gamepad, but you won't get the proper flying experience unless you use a transmitter designed for flying. The simulator will also cost you money, so all together you're looking at at least £50 to get in the virtual air. This does come with its benefits, though - you never have to buy any spares or do any repairs and you can fly even if the weather outside is terrible.
For the best of both worlds, you can do both. Buy a physical quad to fly on nice days, and use a sim for bad weather or days when you want to stay in your pyjamas!
As a little extra side not, be warned that flying in acro or air mode is very different to flying in stabilised or 'angle' mode, so if you learn in angle mode and then switch over to air or acro, the transition may be a little difficult.
So, you know that you want to fly photography/videography drones like the DJI Phantom, Mavic or Inspire, or something like Yuneec Typhoon series. Or you may even want to work your way up to a DJI Spreading Wings or Matrice. Whichever it is, you will be starting at the same place.
There are a few key features that you will notice about all of these quads: they are all large (larger quads tend to be more stable), the all have a gimbal ormoption to add a gimbal, an they almost all will have a companion app to get anFPV feed and extra controls from your phone. These are all for a single purpose: to get you the best most stable possible footage.
As with all of he categories, I recommend you start with a small, toy-grade drone (my go-to recommendation is the Hubsan X4 H107C). This will make sure you have the necessary skills reqired to fly whatever drone(s) you end up buying well, eve if you lose GPS signal. Many people may say that these drones fly themselves, and in a way, they do - you don't need to keep the drone level or actively break, you use the transmitter sticks (gimbals) to tell the drone where to go instead of what orientation you wat it to be in. This is al well and good untl you have to maneuver the drone in a tight space or something goes wrong mi-flight that means you have to take manual control.
When you're looking at what camera drone to get, some important specs to look at are obviously camera quality, battery life etc, however there are more intangible factors that can really make or break a drone. How portable is it? Is there a large support community in case something goes wrong? How is the company's customer support? All of these are just as important s the quantifiable specs.
Most of the time, you can't go wrong with DJI - they are famous for putting out high-quality products that just kind of work. They have, however, been accused of purposefully putting out software updates that reduce the capability of their drones for whatever reason. Obviously I'm not saying that this is true, and the supposedly damaging software update was several years ago and I haven't seen any similar claims since, but it is important that any prospective pilot has all available info. I have personally flown several DJI products and I have neer been disappointed, but a friend of mine is having trouble with the video range on their Phantom, so that is something to keep in mind.
Other companies that make good camera rigs are Parrot and Yuneec in the pro-sumer side of things, with companies like Freefly on the industria side, with drones like the Alta X, which has a lift capacity of around 15Kg.
I can't objectively say what camera drone is the best - that really depends on the applications for which you intend to use it, but make sure that as well as all the quantifiable specs, you will get a good customer service and support experience in case anything goes wrong.
So, you know that you want to fly racing/freestyle acro drones.
The first thing that you need to decide is do you want to fly LOS/VLOS (line of sight / visual line of sight), FPV (first person view) or both?
If you are going to just fly LOS/VLOS, then you only need a quad and a transmitter (as well as the obvious batteries, charger, props etc.).
If you are going to fly either FPV only, or FPV and LOS, then you will need to make sure your quad has an FPV camera and a VTX (video transmitter), and you will need a set of FPV goggles.
Apart from these differneces, you will be looking for the same things in most freestyle setups, and a different set of things in most racing setups (although there is quite a large overlap).
Pretty much all good freestyle and racing quads nowadays use a crabon fibre frame forr good rigidity and strength, and if you want to go at a good speed and have enough power for tricks, you really need brushless motors.
When it comes to the actual flight control hardware, things get far less standardised. At the time of writing, the most advanced type of flight controller you can get uses an F7 processor, which gives you access to all the features in Betaflight and excellent future proofing, as well as ultra-fast processing. The next step down (which is still plenty good for most pilots, myself included) is an F4 flight controller. This also has access to all features in Betaflight, but may not be able to run all of them at as high speeds as an F7 flight controller, and in time may be phased out of usage. This was the case with the next step down, the F3 flight controllers. These are really not what you want if yu're building a high-end or even medium-end freestyle or racing rig.
There are also different kinds of ESC (electronic speed controller). You either get a 4-in-1 ESC, which has all of the ESCs combined, or you get individual ESCs for each of the motors. There are also several different ESC firmwares and protocols. The most up to date firmware is BLheli_32, which is a 32 bit firmware and natively supports RPM filtering which, as you may have seen, can greatly improve flight characteristics. the next most recent is BLheli_S, which can still support RPM filtering but you need to install extra software, which will cost you extra. The protocol each ESC uses is either Oneshot or Dshot, with Dshot being the most commonly used (from what I have seen). There are different numbers after each protocol and differnet sources I've seen give slightly different values of bits/second, but suffice it to say that the higher the number after Dshot, the greater the number of bits per second can be transferred (higher is better).
There are many more features of FPV and LOS acro quads, in fact I may even have to do a page for them on their own, so I'll stop talking about tech specs here.
If you want to get started flying acro, there are three things I can recommend: get started on a simultor (I haven't tried a simulator before and personally like flying the real thing), get started on a small toy-grade quad like the Hubsan (I started on a Hubsan and it set me up well, but doesn't have an Acro mode so you'll have to learn to make the transition from angle to acro), and the final option is to get a small FPV acro quad (specifically a tiny-whoop style of quad). I've heard some very good things about the Emax Tinyhawk RTF kit that comes with the quad, LiPos, goggles, a transmitter and multicharger for a very reasonable price (in my opinion), though this price varies depending on where you get it.