-Build a dispenser right next to the flag or a choke point. When an enemy approaches, blow it up. Maybe bind a key to the "detonate dispenser" command.

-Find really cool places to build your sg, where nobody can throw a grenade easily or even see. Up on a ledge or in a really dark area.

-Work with other engies. Build a dispenser for them, build your sg strategicly to theirs, upgrade and repair their sg too.

-Use your grenades on HWs, EMPs will blow them away.

-Don't build your SG in a place where nobody goes. No kills and no defense.

-Don't build an SG in the corner of a large area. They have a limited range, and the smart enemies will easily take it out.