Get On Seals Spawn Roof
From the seals spawn, you can go into that little building right next to where you spawn, then in a corner, there is a chair. if you stand and walk into the chair, it bumps you up a little. then you can try to jump THROUGH the roof, and if you hit the right spot, it ill put you on the roof of the building. I also take no credit for this.

Get Behind the Fence #1
This is explained in a Seals Perspective. When you smoke turn so you are facing your spawn building. Then run passed your building and you will be able to see a little mountain you can jump on, Get to the very top of the mountain and turn around and face your spawn building again. Now turn a little to the right, you will see a fence. Aim a little bit to the right of the fence and then run and jump, you will then fall and slide and get behind the fence, this might take a while because it is hard to find the spot, and we do not have any pictures as of yet.

Get Behind the Fence #2
Seals right, Terrorists left. If you are a seal, its before the first bridge, and if your a TERR, its after the second. There is a little ledge on the mountain that you can jump onto. Once you are on there, turn 180 degrees, and run and jump to where you think you are jumping too late, and u will hit the mountain, and be forced up. Give it a couple tries and try your own different little spots.