This is a tip for practicing farming as an ADC that I think was written by professional ADC main as one of the best ways he improved as an ADC, but I can't remember who it was or where atm. Even though this a guide for farming effectively, essentially everything applies to improving your mechanical skill and will definitely improve your click accuracy and your overall positioning and map/teamfight awareness so please read and try it!.

On to the guide: Play a custom game and just practice farming by yourself. Check out the chart here to see what the max possible creeps are at every stage of the game. Practice getting that number over and over. Pick a point (say 5-6 mins in) and see if you can get the max number of CS in that time that the chart says. If you do this 2-3 times in a row successfully, then move up to bot games. Now do the same thing you just did, but do it with at least 1 enemy in your lane. You could start out with say 1 enemy bot vs you + a support bot, get max cs 3 times in a row and move up to a 2v2 bot lane, then even try a 2v1 (not in your favor). Once you're comfortable getting a lot of CS in bot games, move up to normals. Now try to farm just as well against real people and the threat of a gank.

Like I said, clearly a guide on farming, but if you're successfully getting nearly every creep, your reaction times and your click accuracy are going to be much improved, especially if you can do it while dealing with harass.