About how to aim I haven't read too much, but some players have problems with it.

At the beginning, getting used to the different heights of the terrain can be hard, and your shots will hit the ground or an obstacle (on the other hand, once you get used to it you will use terrain slopes as cover, and you will flank enemies using it in your favour).

What I do when shooting is placing the cursor on the enemy, or a bit further, so that the bullets will go to that very small area of terrain - not higher not lower-. When using a rocket launcher, which is not as accurate, I aim a bit passed the enemies, but always keeping them in the invisible line between the weapon and the cursor.

Maybe some experienced players could share their thoughts here.