Just started this and am having some good mindless fun. Rocking a Storm AoE build and having a good time. Any recommendations for noobs?
Don't sell stuff unless you really need the credits. Just donate unwanted items to rank up crafter. Except for uniques.
They don't have much value in credits, so if you can (that is, if you've got enough stash space), try to hold onto uniques so you can exchange duplicates at the crafter.
Don't bother picking up all the crafting ingredients you find. Just get what you need, or you'll be running out of space fast.
Legendary quests (start at lv20) are still, mostly, the best source of XP.
Try to focus leveling one character first to 60, for hero synergy xp. IIRC, you get like 30% or something for getting one character up to 60. You can see the details of this in the tooltip in game, under stats of your hero.
Game is pretty easy overall, so don't worry about your build until much later. Try out different powers and see what works for you. You get 3 free retcons per hero (one from each difficulty).
I'm not sure if this is mentioned in game, but I'm 89.6% certain you can use the team up inventory space to store stuff even if you don't have a team up.
For scheduled/times events, promo codes (to redeem for free in-game goodies), and general MH news,
http://www.hub4heroes.com/ is pretty good.
People will post the newest promo codes here and in game (if you're in the supergroup), but some older codes may still work, so still worth checking/trying out older codes.
All the wikis are horribly outdated. Don't bother looking at them.
If you want most up-to-date info on all the stuff in the game this
compendium offers everything.
If you prefer something that looks nicer, there's a website version
here
Not as up-to-date as the google docs, but still much, much better than the wikis.