The auto-setup feature is stingy with ammo and backup weapons. Be sure to bring extra ammo and a sidearm for each of your soldiers.
Don't save the game until you're sure you've cleared an area; you can make life difficult by saving right when you're coming under fire.
Snipers aren't as important as they were in the original game. You want at least one sniper on each team, but a lot of Devil's Bridge consists of close-assault firefights.