Glitches
A glitch is a more powerful version of a blind. You can stand in a glitch and see a sniper in a particular position, and they will never see you.
The bottom of every wall has lots of glitches that can be exploited. Each type of pillar has a whole bunch of glitches that can be exploited. If you see the same wall/pillar repeated in multiple places on the map, the same glitches will work on all of them.
Video walkthrough of all the pillar glitches, as well as some discussion on how you'd use glitches in your game.
See this old forum thread showing most of the useful wall glitches on the map:https://www.tapatalk.com/groups/sniper_league/wall-glitches-t4391.html