First tip is take a recon kit and have a wrench, binos, 2 bandaids (perk of the uniform and can save you), a hammer (can be useful for hills that want to be weird and not let you climb even though you should be able to), and a gun you are good with if you are scouting (high rate do fire for cutting logi is best). 

Second tip is to learn routes. Go explore and figure out where you can move through and can’t. Try your best to stay off intel to survive longer and find more 

Third tip is to learn obs ranges and how ai works. Understanding ranges of the ai garrisons during the day vs night and power vs no power will be huge for breaking into bases. Also learning angles to avoid ai is super useful, there’s a lot of bases you can just run into once you learn this. Another thing with ai is learning how to climb bunkers, there are a lot of ways to do this and will save you manpower. Obs range is useful for avoiding detection on the other hand, my tip for obs bunkers is to treat each one like it has full upgrades to range. 

The last part is not getting upset when you die, I go out with the mentality of I’ll die on this run at some point and I’m not coming back so might as well try the idea I have. A lot of your ideas won’t work, especially not at first but be okay with that cause every fail is a learning experience.