Not sure that I have great tips, but two things you need to learn is where the choke points and how to strafe a corner.
Choke points are where the two teams would meet if both ran to the same spot at full speed. Know how far you can make it out of the spawn before you make contact with the enemy. Early on in the games release frag those spots and keep scopes on them, you can almost guarentee you'll find someone there.
Next is strafing a corner. Since it's a third person perspective people can see you before you see them around corners. I usually keep my crosshairs close to the corner just in case someone pops from behind it. When I approach a corner I strafe to the left or right away from the corner so you can get a better angle on it. If someone pops from the corner quickly switch your movement to the opposite direction in which you were just moving. Most of the time they will continue to spray in the direction your heading, so if you move the opposite direction, it may buy you an extra second to react.
Not sure that makes sense, but it helps me alot.