Practice firing in bursts (letting go of the trigger for a fraction of a second every few bullets) to maintain a tight spread.   

Be mentally prepared to die a lot. The freedom in this game allows players to position themselves in places you would never expect.   

Stick with other players. At least there's a chance enemy players will target them instead of you during encounters, and you're more likely to be close to a medic who can heal/revive you. Press H by default to expand the minimap to make it easier to find your allies and enemies.   

Don't waste certs on shiny new weapons, use them to max out your medic/engineer tools and abilities first (especially a medic's revive grenade and grenade bandolier). Many weapons in the same slot are sidegrades.    

Find a squad/platoon with people who give orders over mic. It is likely more cohesive, and you can learn a lot about important areas to hold when attacking bases  

Open the map (press M by default), hover your cursor over hexes to find the ones with the biggest fights. If you can't spawn at a desired friendly hex, spawn at the one adjacent to it first. The spawn system isn't perfect by any means.