I'll start by saying this: there is no quick fix to make you better at a game. That comes from playing often, making mistakes, learning from them and going again. But there are always things you can do and products you can buy that will help you on your way.
A good controller is the top of the list if you're playing on Xbox One. Those like the Xbox Elite Wireless and Razer Wolverine Ultimate give you more customization and flexibility, a higher quality, better feeling product and with things like rear mounted paddles, they can certainly help get an edge in a fast-paced, competitive game.
Something else that can help is a good pair of thumbsticks. I've been using KontrolFreeks for a couple of years now and no, they didn't single-handedly make me a better gamer. But they did help me become one, and I know a lot of other folks out there swear by them too.
What is a thumbstick?
A thumbstick is a disc that you put over the top of the analog sticks on your Xbox One controller. They're usually made of rubber with various textures to provide a larger, more comfortable, and grippier surface for your thumbs when you're playing a game.
Som thumbsticks, like KontrolFreek's, can alter your gameplay. In the same way as you may use the taller sticks on the Xbox Elite Wireless for finer control in a game like Call of Duty, KontrolFreek has some thumbsticks which can replicate this by adding the better, gripper surface for your thumbs.
Here's the thing: whichever Xbox One controller you get from Microsoft, the top of the analog sticks isn't a particularly great surface. In many cases these thumbsticks will only work on Microsoft controllers. I can't use mine on the Razer Wolverine TE, for example.
What they're like to use
The reason I personally stick with KontrolFreek is the design. Generic thumbstick grips can just be a rubber disc that wraps around the analog stick. Even on the low-profile KontrolFreek sticks, you get some form of rise. They clip to the perimeter of the analog stick so you get full coverage and an increased surface area.
Even this slight rise is beneficial in adding extra control. The taller the stick, the less pressure you'll exert on the controller and it should be easier to do things like control recoil. Combine this with a larger surface area and just a better surface for your skin to grip to and you have a much different experience.
Again, these alone won't improve your gameplay, they're just another tool. But the clue is in the company name: It's all about control.
One of the other things I like about these sticks is that besides rise you can also turn your Xbox One analog sticks domed rather than concave. Again, Elite controller owners have this option already, and some folks much prefer a domed surface in some games. Personally, I play Call of Duty with two domes most of the time because I prefer being able to roll my thumbs. With a concave surface, I don't get the same feeling.
Are they worth it?
Honestly, yes. They're not particularly expensive and I've long enjoyed using them. The variety in heights and styles gives an opportunity to change it up on a game by game basis, and I do believe they've helped me a good amount in a number of games.
They haven't single-handedly improved my performance though. As I started out, a good quality controller, some KontrolFreeks and practice are what you really need. If some like an Elite Wireless is out of your budget right now, definitely start with some KontrolFreeks.
If you've any experiences to share be sure to drop them into the comments below!
