Let's post some tips and strategies for Halo 2 guys. I only know of a few but I'll share. Leave tips/strategies for gametypes, maps, weapons and just straight up killing techniques.
In the Waterworks level, you can drop down on the opposing teams flag through the roof (out of a Banshee even) grab it, take 3 steps towards the window, and then squeeze the left trigger to throw the flag, it'll go out of the window, where hopefully your team can drive by and snag it in a warthog.
In the Blood Gulch level (keep forgetting the new name) you can jump onto the hood of the Banshee if it's in the bottom of the base and grab the flag through the floor of the flag room.
If your making a flag run back and your a freaking Killer (capital K) toss the flag and kill the pursuers and hopefully wait for back up. Too often the flag runner get's shot down and the opposing teams sets up camp around it and picks off your buddies one at a time. Unless your strategy is just to get as close to the base as possible.
Alot of people know this one, but in Waterworks you can use the Wraith tank to push the big green crate/boxes to effectively block ground level entrances to the base, forcing the opposing team to enter/exit from the top.
Sticking together is better unless your a Killer (capital K) cuz you can overwhelm single opponents, but beware the rockets if your all crowding around.
Stay moving at all times when your outside due to the snipers. At least this way only the really good guys can headshot you from across the map. (zig/zag)
The rocket launcher warthog and the Brute Shot's explosions give a healthy concussion to buildings that can add to the confusion inside. To me it's extremely annoying to have the rocket warthog driving around outside the base constantly shaking the building.
Let's hear some more.