hi guys, ive wanted to increase infantry & navy rank for ages. whats the quickest way in the game currently? in the old days i think a point defence for 15 minutes would give you XP if you didnt die.

In my experience, spawning armor and defending a town works pretty good.  Easy kills, you get points for defending a control point and you don't have to drive anywhere to RTB.  

During intermissions, OIC will (usually) put an attack order on a bridge that's right in front of the docks. So you'll spawn a fairmile and keep attack that bridge, respawn and get 30 points. You'll keep doing that until you get high enough rank. You could get to rank 5 in about an hour.

If you're not into stat padding, a good 'legit' way is to attack/defends towns with the navy's army. Similar how the air force has their own army. I personally think AA is the best way. It's fairly easy, and you get 30 points for each kill. But you can still rank up just as fast through tanks and stuff.

As for army, I leveled completely by AAA. It's a very good way to get kills, and after a few days you get the hang of it and learn where to aim/lead. Every kill you get (almost) 30 points.

Join the HC and learn how to run the game brigade movement mechanics.  Simple as that.