At the beginning of Part II of Delta Halo (You Break It, You Buy It), you can use the ghost's boost to power your way up a hill on your right (as you enter the area, this hill is at about two o' clock). There are several neat things about this spot.
One, there's a rocket launcher right beside where some unfortunate ODST landed, which contains six rockets.
Two, it gives you an excellent vantage point from which to take out ghosts with your newly found holy grail.
And three, you can actually sneak up on the covies in this area. If you get up the hill quick enough (not that difficult), then they won't know you're there until you decide to announce your presence. Once up top, you can drop straight down undetected from where the ODST's pod landed. There are several entrances to the pillared structure. Personally (and for stealth purposes), I like the second closest entrance to you as you hit the ground, which you'll recognize from the thick foliage occuppying it. From here, there are several things you can do. Sometimes, the Elite patrolling the hallway with a ghost will slowly drive right by you. You can give him one hell of a surprise by quickly running up from the foliage and boarding his ghost. The drawback, however, is that there are two pesky jackals and a grunt nearby who can take you down by the time you actually gain full control of the ghost. So what I like to do is to take those three bastards down first while the ghost Elite is driving the other way, and then wait for the ghost to come to me so I can board it. After that, you can simply get the hell out of there. The cool thing is that by doing this, you can prevent many of the ghosts from appearing. In the very next area, there are usually a bunch of ghosts coming up the ramp, if you play it traditionally that is. Not so if you use this strategy.
NOTE: This tip isn't necessarily to help you stay alive longer, just to show you another cool way to approach this area. I'm just trying to add some replayability here. Besides, Mike Miller said he liked it, so it must be a good tip!