First of all, I'm not a main awp player... I play second awp and entry in my team... but here's my experience as a secondary awper in a semi-pro team... As well as some inputs from our Main awper.
Most important thing is that you need to figure out your style of awping. Either be an Awper like Device (best case scenario imo) or an awper like woxic (ofc 2019 woxic, the current one sucks).
If you play with teammates, (i.e 4 or 5 stack) I suggest playing extremely passively. Device is a model example of a good passive awp player because he doesn't take many risks, doesn't take up too much space in the server, supports his aggressive teammates with utility, and still manages to put up good frags on the board. So for playing super passive, learn what angles to hold, and try to read the game in such a way that instead of you peeking into enemies, they peek into you. 9/10 an awp would come out over a rifle in that case. Ik that can be tough but again, this is only if you have teammates. Since those guys can communicate info and you probably have a better understanding of the game.
On the other hand, if you play solo... being aggressive is not something that you should rule out. But by the general rule of thumb, Awpers are not meant to be super aggressive. In such cases, your own gamesense becomes the top priority. It's up to you to decide if you want to hold an angle and hope someone shows up, or flash and take a peek... you need to make these decisions on your own.
And as for super aggressive awping (i don't recommend it, if you're having a bad day, and you miss shots when playing aggressively, it's omega tilting) - reflexes and crosshair placement become more key. Think 2019 woxic. You need to be very confident with your aim to be aggressive all the time. And it's not a myth, a higher sens can actually make you a better *aggressive* awper. Keyword, Aggressive... because you'll be faster in flicking and adjusting. On the other hand, it can make you a worse passive awper.
So all this was the style:
Now lets talk practice...
Tbh nothing better than entering DM and just grinding. Ik it's very typical but it's THE best exercise for your reflexes and muscle memory. If you play DM with the awp for like half an hour per day, then hop into a game, you'll feel much more confident with it. I used to do 1000 kill Warm up before any big game (well "big", all we did was play some local LANs).
My team's awper used to do the same, here's what his daily routine was:
100 M4 (100 Aug at the time because it was the meta)
For a pre-big-game session, this turned into 1000 kills:
100 M4 (aug)
100 Scout + Deag mix
Another thing is, you have to learn how to play fearlessly. And there's a difference between "fearless" and "reckless". You have to play with confidence but that doesn't mean that you should unnecessarily peak corners. If you aren't confident in your awping, grind the DMs until you are. You CANNOT be an Awper in higher levels (say Level 10+) if you're not confident in your playstyle and/or your skills.
Apart from this, the usual decent mouse + decent mousepad helps although it's obviously not the end of the world if you don't have a super expensive setup. And that's about it! Nothing stopping you from rekting them scrubs after this. Lemme know if you wanna know anything else :)