Everybody plays a little different but the key concepts are the same. Take as much free territory as you can while keeping your stronghold surrounded and protected from other teams.
Stack all your reinforcements on a single hex and march through enemy hexes with them.
Some people save all the strongholds for the end. I just do them as I come to them assuming I have enough fans to play on my preferred difficulty.
Steal only enough fans to satisfy any steal fans mission and play those games on difficulties you feel that you can beat.
Sim every game that is not a stronghold or steal fans game (and those can't be simulated)
This can all be done by only ever having 1 fan per hex. You will occasionally lose hexes to other teams but you should gain more than you lose every turn. Just keep and eye on your strongholds and if you see a team approaching it with more than say 2 fans then reinforce there next turn and retake the hexes.