I started a week ago and here are some nuggets that I have learned from a week of play.
1) Unless you are a scout then CAMP. Experienced players rely on new players to take all the heat for them. Stay behind the higher HP tanks and in cover. The people telling you not to camp are camping themselves and waiting for you to make the first move. Don't fall for it.
2) There is absolutely no point in capturing the enemy base. It awards you very few XP and you will invariably be a sitting duck. If someone else goes to capture, follow and get the points but never go yourself.
3) Hit as many different targets as possible to get maximum score. Never commit to killing anything unless you can do it in one shot. Most enemies are just trying to drag you out of cover. They might look alone, they aren't. Also, your own team are waiting for you to reduce a tanks health so they can steal the kill for their own XP. Unless you can hit and run, wait for a tank to be killable before you commit.
4) Loading a level, charging the enemy and getting a hit might get you killed in less than a minute. But you will invariably only get about 60% less XP than the top player. If you die fast you can switch to another tank and do the same there. People who care about kill ratios are the kind that pay to win. Just play the numbers and turn over levels as fast as possible. You can go back to garage jump in another tank and do the same again while you wait for the round to end.