Hi. Just thought it would be nice to have a post where people can put little things that they wish they'd known/realised from the start.
1) The Tab Key is Your Friend: Tab allows you to cycles through all enemies within your view screen. Invaluable for flicking between multi-targets so you can keep control of the group you are fighting.
2) Read the Archetype Boards. Before creating a character, I repeat again READ THE BOARDS! Other people have spend hours playing almost any combination of powers you are interested in and have shared their experiences here. The boards can give you GREAT advice so you can plan you character better and know which powers work well with your concept, which don't. and which plain suck (Choaking Cloud I'm looking at you!).
3) The 5th Column Ambush. Apparently ambushes are quite common in later game, however the 5th Column will come after you right from the start! Nothing worse than doing a mission and exiting low on health and end (yeah you get a heal when you leave the mission but not up to full if really down) and casually making it back to the trainer/contact just to get flamed and shot as they jump out at you unexpected.
4) Hover Rocks: There is a lot (oh my is there a lot) of fierce debate over which travel power is best. However, I would like to claim of all the travel prerequisits you can take at 6th lvl, hover is the the best (expect when Hasten fits you character!). Ok its slow, slow, slow... but when you are hunting Circle of Thorns in Kings and you dont have to keep going up and up the fire escapes to find someone else has beaten you to the green glow on the roof you will love it. Even better it gets you out of melee range if you are blaster/controller/defender and gives you a small defense bonus even if you are in office block corridor and can't fly up.
5) Freedom Corps Buys Training Enhancements For More: Need to sell all those enhancements you get for top dollor - head for Freedom Corps (one in Steel Canyon right on the Bronze Row map icon north of the tube station). However, its not worth it until you are at least level 4 or so 'cause unless you are very very careful you are likely to be killed by a random street mob on the way there.
I am sure folks have loads more they will love to add

Go for it guys!
Mikes
Prismatic Star (18th Rad/Rad Defender - Triumph)
The Extremist (6th Rifle/Dev Blaster - Triumph)
The Redactor (5th Ill/Emp Controller - Triumph)