Play in co-op mode in any level (Outskirts recommended). Have one player jump on top of the other. Then, have the player on top jump again and keep pressing [Jump]. Then, have the lower player jump immediately after the first player. If done correctly, the top player should land on the lower one (who is in mid-air), then jump again. You can use this to get on top on locations you cannot reach normally.
This trick can only be done in co-op or multi-player mode. Get next to the structure that you want to climb. Have a player take out his plasma sword. Have the other player stand on top and keep jumping in the direction of what you are climbing. While player two is jumping, have player one look up and use the "Sword cancel" trick. If done correctly, you can reach any area in the game as long as you do not exceed the invisible barrier.
On any co-op or multi-player level, have you and a partner find an area where you need some kind of boost to get to a higher location. Have your partner crouch under that area. Jump on your partner, then jump (without falling off your partner) as your partner un-crouches. This should give you a big enough boost to let you jump up to your destination.
You can jump higher by simultaneously pressing [Crouch] while in the air after a jump.