1. When you start on container city as the resistance and your objective is to blow up the barricade to get your bot through, well you know on the left of that there's some stairs that lead to a door that can be opened if an operative hacks it, if you're a light class you can wall jump off the left wall and climb on the ledge on top of the door to get to the other side.
2. I forgot the name of the map but you know the mission where you need to repair the crane and there's two barricades that the opposite team can build to hold you back, if you go to the side barricade and go to the second level you can wall jump and push yourself to get a hold of the other ledge, with that you can get in even after they build barricade, I know it's a bad description but it's the best I can ^_^
3. you don't need a light to do this you can do it with a medium too. But on aquarium where you need to escort the bot to the boat there's a point where you need to get the bot up some stairs, right where the stairs start if you look to your left and up there's a vent that you can climb up to cause there's some boxes that can let you get up there =]
I hope this helps guys, sorry if I wasn't very desrcriptive