Halo Reach Jump Spots
Halo Reach is one of the most unique games in that it has very accurate hit boxes and collision detection, and no invisible walls around objects in the middle of the maps, something that Call of Duty doesn't have. The upside of this is that there are a number of hiding and jumping spots that can be reached on a variety of the maps in multi player games that can allow you to get the jump on other people.
Try these jumps out in custom games before you do them in matchmaking so you know exactly how to do them. They can give you some interesting sight lines, and dislodge people located in high traffic areas.
These jumps tend to be super effective, and are very easy to do in comparison to other jumps and spots on other maps. They allow you to take out people in the sniper tower easier, and give you elevated DMR nests that you can use to get a few easy kills at the start of the game.
Some of these jumps may no longer work, as Uncaged was released shortly after this video was made, but they are still useful in matchmaking. Try them out, adapt them how you wish, but be careful; there is a very real risk of falling right off the map when attempting trick jumps on this map.
While many of these jumps are pretty standard, the ability to run to the top section of the red spawn is an amazing asset in MLG or Arena games if you don't have access to a jetpack. From up here, you can snipe or DMR enemies, and still have enough cover to avoid return fire. Just remember to drop down if you start getting grenade spammed.