* No lone-wolfing - stick to your Squad to start with
* Choose a role and PLAY THAT ROLE i.e if you are Assault, then Revive. If Support, drop Ammo. If Recon, then spot and Soflam and place your Spawn Beacons intelligently. If an Engie, then Repair and provide Anti-Vehicle Support.
* Don't be afraid of being killed but don't waste your tickets meaninglessly - basically, PLAY THE FLIPPING OBJECTIVE. Don't play Rush and camp in a corner for the whole map etc.
* It takes time, at least 10 to 50 hours per Kit imo, to figure out what your specialism is and how you are most effective on the Field. This is different for everyone - but there being so many play-styles is one of the best things about BF
* Experiment with load outs and add ons till you find a sweet-spot
That is basic advice to start you off - lmk if you want anything more specific.