On top of what Xeno says you need to get your confidence up. the issue with aim maps and training maps is they don't introduce movement, positioning and peekers advantage nearly as much as real competitive games.
I play primarily as an entry fragger, and I spent a lot of time, funnily enough with Xeno and others learning how to enter sites. You should try to set up your game so that you take the enemies out of your comfort zone. Never try to work on reflex and aim.
An example is entering A ramp on mirage as a T.
We have one player in palace, he waits with flashes.
One player from T spawn smokes CT, one conn/jungle, one stairs.
When the smokes pop the guy in apps flashes twice, on the second flash I run out, and clear shadow (under the balcony) while smidsy/cat/whoever watches triple stack.
What we did there was block any supporting players off, and put them out of position with smokes and flashes which reduces the amount of things you have to do in an aim battle.
To work on Xenos point in mid. If you want to peek mid as T on inferno, pick a side. Communicate to your teammates, I want to go short. Once you have your side picked, take away the other side, use smokes, flashes and coordinate it so you are going and the only thing you have to do is take care of the guy now. You have reduced every other factor and turned it into an aim duel on your 1v1 hs server. If you know where he is already, you have that on him also.
The Cloud9 player has some sick videos on crosshair placement, as well as former iBP player Steel having a tremendous amount of info on how the mechanics of CS:GO work.
tl;dr - an aim duel isnt just an aim duel in a comp match, push your enemies into a position where you have complete advantage.