Silhouetteing
I have noticed playing gallipoli that a lot of players don't really get that silhouetteing is a thing, which is fair cuz its not intuitive.
Basically this is kind of a PSA.
Don't try to snipe, or stand in front of, open sky or something in the background that will provide a high contrast between you and whatever is behind you.
It makes you trivially easy to look for and shoot, so try to avoid being places that do this too much. I will see many snipers sit on rooftops and such, but by doing so silhouetteing thsemselves against the sky behind.