4. You'll want some crowd control

Click and watch them fall

Since any character can use any combat ability, make sure that every one of your characters has some crowd control in their back pocket. You'll be fighting swarms of monsters more often than any single big boss or even PvP battles. Trust me, it's going to get dull if your uber-powerful marauder can flatten each single small critter he meets, only to have another fifteen standing in line. Give him some crowd control and he'll be a happy camper. Or critter-smasher, whatever works.

It doesn't even have to be very impressive or powerful, just make sure it's there. You'll be doing yourself a huge favor.