I posted this on the official forums in the hope of reaching as many pubbies as possible, and robo suggested on Discord that I cross-post it here. Not expecting it to be news to longstanding Labbers, but if it helps someone...
Episode 7 is upon us, and yet again we're plagued with people who seem to want to play Frontlines in the most self-defeating way possible and ruin the mode for everyone else, so here's the Idiot's Guide to Frontlines.
Let's establish the victory conditions, and it's not what you'd expect: picking up a win or a loss is barely relevant. You'll still be making credits hand over fist either way. What you want whether you're attacking or defending is for all bases to be captured during the course of the game and to run the clock out blowing up each other's tanks. That means that everyone has the most possible time to farm rank, and you want to farm rank because one game at General is worth more than 2 games at Captain, 3 games at Lieutenant or 8 games at Sergeant (and that's just in terms of Frontline progress, you also get the Battle XP multiplier too).
If you're attacking, stop trying to take out the objectives. All that achieves is ending the game early and denies you and everyone else on both teams rank and Frontlines XP. Focus on capping all 6 bases then use the time you've built up to kill enemy tanks.
If you're defending and the clock is running out, allow the other team to cap and prolong the game. You don't want too much time on the clock because uninformed players will rush to hit the objectives instead of capping bases, but conversely you don't want it to come down to the wire and the attackers be prevented from capping and adding time to the clock.
Finally, the best way to gain rank is capping/defending. This makes every game as a defender a balancing act, because you want to be doing the majority of your damage in and around the cap circles, but not when the clock is low because that might lead to an early win/loss.
It's unfortunate that any of this needs to be said, but it's a consequence of Frontlines being a fundamentally broken game mode where the incentives don't align with the victory conditions.