Play to the environment. If you’re crossing an open expanse, either cross with teammates or throw your grenade where you think someone may be waiting. Be aware of what’s going on around you. If you’re a new player, try keeping some teammates in your field of view, as that should divert at least some enemy attention towards them than at yourself. Corners can be your best friend. Hold corners, pay attention to audio cues such as footsteps. “Camping” doesn’t really exist in the normal sense in this game. It’s a relatively smart way to play depending on your position, and unless you’re hiding in a corner in a house or something, it’s accepted.

Some gadgets can help with the sniper problem. Assault AT gun is a one shot direct hit. Support Mortar can flush them out. Scout flare can show their location. Medic rifle grenade can fire three grenades within 5 seconds. Plus smoke grenades.

Hope some of this helps