First of all, stay out of Ironforge
When I played in Alterac Valley in World of Warcraft, I found that decreasing my video settings helped out a TON. I was lagging a lot in the battleground to the point I couldn't even lead my raid. The only way I could was if I turned off my sound for my game and decreased my video quality. Check something up that alley?
Also, are you running through a router? I had horrible problems with my routers with World of Warcraft. I don't know why.
Just my tips from my expeiriennces.(spelling plz lol)
"Alliance FTW"