Heals wake people up. Any change in HP will break sleep, including both heals and damage.
Never try and pull a boss from a group… he will bring all of his lieutenants and minions with him. Instead, go for the minions that are walking around and not too near the group, or the ones that are facing a different direction than the rest, they tend to be the easiest to pull alone or in small groups.
A quick way to get out of debt or gain some quick influence is to exemplar to someone in the 1-10 level range. To do this, have them on you (or your name in the team window) and select "invite exemplar", accept the invitation and you will notice many of your powers grey out. You cannot use these powers for the duration of the exemplar, but soon you should be out of debt or have the influence that you needed.
Team often, and team with people you know; this is where people tend to have the most fun and the quickest level gains. Pick up groups can be fun, but they can also be frustrating. Teams work best when people know what the other players on the team are capable of.
Choose your powers wisely. It is usually a bad idea to have more than one transport power before you hit level 28; around that time some people will pick up a second transport power, especially so in the case of Super Speed and Super Jump. On the flip side of the coin, most people have some form of transport power when they hit level 14.
Make your power pool powers count. They aren’t as powerful as your primary and secondary power sets, so if you have something that is very similar to a power pool power that you are considering, think hard about it. Many people will choose the fitness pool for the Health and Stamina powers that are available at the later levels. Another common choice is Hasten from the Speed power pool.
Avoid over-using power pools. You are only allowed four different power pools, but you can pick as many of the four powers in each of those pools as you like. Generally it is not a good idea to get more than five or six pool powers over the lifetime of your character.