What strategies do you use in Battlefield Bad Company? Know any good tactics or spots?

I only have limited time to play the demo and i want to make the most of it. I was wondering if anyone knew any good spots to camp, sniper spots, weapons skills tactics I might use to crush the opposition.What strategies do you use in Battlefield Bad Company? Know any good tactics or spots?
if your attacking you can usually get 100 points with the attilery gun(howitzer). I like using the support. You will see crosses on your map where your teamates have low health. throw the health pack at them and you will get ten points. Also you can heal your self. If someone is shooting at me and I don't know where there at then I will get some cover and then heal my self. Also the support has the ability to repair vehicles. Sometime people abondon vehicles cause they are worried about them blowing up. You can repair the vehicle then take it. When people are running around use the machine gun on the tank to cut them down. If there in a building then blast it with the tanks big gun.. I was playing the other day And I got a bunch of people with the support motor strike. They defenitley upgraded the mortor strike from battlefiled 2What strategies do you use in Battlefield Bad Company? Know any good tactics or spots?
Run to the hills, snipe your heart out and if you have the laser designator, use that. Ummmm, take a boat and drive behind enemy lines and take out everybody. And finally, instead of walking through doors or walking around buildings, blow a hole and the wall and jump through it.