Here is a good list of Common Sense Tips that aren’t Commonly Heeded for Heroes players.
Number 15 is huge:
Show up to objectives even if you are in the middle of mercs. That
knight camp or ogre camp isn’t going to do much against a dragon
knight, garden terror, cannon barrage, etc. Especially if it results in
a lost team fight. Seriously, LEAVE THE FRICKEN MERCS AND COME HELP!
Another great one is in comments:
My only addition. If someone pings Retreat. Fucking Retreat. They
usually have a good reason for doing so. Many times they see something
you do not. And when you do retreat. If a tank or someone with high
health or CC tries to slow the advancing team from catching up to
stragglers this DOES NOT mean engage again. B home when safe and top off
your mana and health.
–and some of its follow up comments on retreating: If a healer throws a shield/heal on you when retreating, it isn’t a sign to re-engage. And that tank/CCer that goes back to slow usually has the health or an escape ready or else are willing to sacrifice to save some DPS and/or Support.