Watch the tower, there could be someone climbing already. But even if you miss them getting on it, with Assault rifle it is easy to take them from the bridge. If they start tossing grenades at you or you pinned down behind those crates, just make a hole in the bridge behind you with grenade launcher and jump under.
From under the bridge there are plenty of nice spots to take down various target. Watch your back though, and it is good to have sniper close by. If you are under the bridge and someone is on top of it, again grenade launcher is your friend to open up the bridge.

Grenade can reach from one bank of the river to another, and for some reason I was able to take wall from ground and 1st floor with 1 grenade in the building across the river. Then you can see the fuckers hiding there and take them with rifle. Fuck the AN 94 is fucking brilliant long range. Oh, and the roofs of course. Getting to lofts and on top of the roofs is just so cool, great coverage.