One thing you can help do to compensate for bullet drop is adjust your zeroing. This down by pressing Page Up to increase it, or Page Down to decrease it by default. You can change the key mappings in the settings. Note that you can only see how far your zero distance is when you are scoped in (first person perspective).
If you are exactly 100 meters away from something, and your zeroing is set to 100m, your bullet should hit exactly where your cross hair is. If you are zeroing for 300 meters and your are exactly 300 meters away, your bullet should (again) hit exactly at the cross hair. If you don't want to use zeroing, you'll have to aim above the target you are trying to hit to compensate for drop. Both methods will likely result in trial and error, unless you are very good at estimating distance. On the flip side, if you are using zeroing, and you are compensating for too long of a distance (say 500 meters but your target is really at like 450 meters), you'll have to aim slightly below them instead.
You really just have to get a feel for the bullet drop in the game.
I think you can setup a custom match where you could at least practice. As far I'm aware, judgement is the only way to figure out how far you are from a target.