Bring healing pots!
Clerics die! People get beat up badly in epics, so cleric SP is also at a premium.
Help them out! Heal your self.
And if at all possible have a method of rezzing others.
Like I said, Clerics die!
I've seen epics fail for no other reason the the Cleric died, no one could res him, and no one (but me) had any method of self healing at all!
Don't release!
you can't get back in. And someone else in your group might just pull off a miracle.
(and in Epic Chrono the soul stones get transported to a rez shrine on a wipe.)
Gang up on things!
Epic mobs have high HP. it works much better if the whole party teams up to kill things one at a time instead of trying to solo kill something.
And while you do not need some super DC caster, effective CC makes things much easier.
(and Fighters can CC too)
Sunder, sunder sunder!
You may have super Str and never miss, but non-full BaB classes struggle against epic ACs.
Don't get overconfident!
This one is for me.

I see that I am fighting against whimpy Hobgolbins that I was beating up at lvl 4 and I think I can just take em on with no trouble.......then I find out otherwise.
Related to this is to remember that a lot of players are a whole lot better than you are.
Other people "can" solo epics. You probably cannot.
Other people will charge right in and not work as a team....because when they run the same quest with their uber guildies they can do that and still succeed.
Dount count on that in a PUG of new lvl 20s.
Epics are doable by new guys, but you need to work together.