I am not an expert at this game - far from it. I just threw together some observations that some rookie players make the mistake of doing and how to correct them.
(In no particular order)
1. Cater your player to your play style.
If you are good at throwing the body and forechecking, playing as a dangler does not make sense. Choosing a sniper does not allow you to become Petr Sykora. If you suck at scoring goals but you can pass like its nobody’s business, change your player type to a playmaker. Play to your strengths and your statistics and your record will improve.
3. Pass Smart.
Long lead passes. When they work they are amazing. But they are like the deep pass in football… used sparingly and when appropriate, they can result in points. However, if you go deep too often… it will be intercepted and then you got a pick six. Be careful passing into the offensive zone because many human defensemen like to step up and give out free candy at the blue line, especially along the wall.
Don’t be afraid to dump it in rather than pass it in. There’s nothing like a good dump.
Do not be afraid to drop the puck back to the point. A point shot is a hell of a lot better than a weak wrister from the half boards. Or a turnover. Get the puck back to the defensemen and get into position for a deflection or a rebound.
The left wing covers the right point – while the right wing covers the left point. The center patrols the high slot. There are other variations of defense but this is the simplest.
On offense, if you are a defensemen do not go in deep in the offensive zone unless a forward drops back to cover your ass.
If the refs called interference penalties online, the entire game would be played 3 on 3. So instead they replaced interference penalties with cross checking. They only call cross checking when it is extremely blatant. Therefore, do not hit someone that does not have the puck!
There are two types of cross checking penalties: the penalty formerly known as interference, and the horrible, frustrating, the-puck-was-at-my-feet-why-would-you-crosscheck-the-defender-instead-of-shoot-the-loose-puck-into-the-net-you-stupid-dbag!!!!
I know everyone out there has taken both types of penalties. While the second one is a control snafu (yeah I said snafu, wanna fight about it?), the first one is usually avoidable. If your team stays disciplined you will get plenty of powerplays. The tripping and high sticking penalties are harder to avoid.
I took this one from http://www.sportsgamer.com/content/2177/ . They have a more detailed write up over there but when you have a shot on goal with the puck in the slot like this: 
Where should you shoot? Glove side, stick side, or 5 hole? It depends on the situation but because of the range of motion of the glove hand, going stick side is a better option unless the goalie is off his angle. Plus the stick side gives juicy rebounds while the glove hand does not. Do not be afraid to shoot 5 hole as well. The hard slapper over the glove hand sure is pretty but poking it through a goalie’s legs is almost as satisfying. Give it a try.
If there is an over aggressive defense that is constantly stepping up and hitting you at the blue line, throw a little Left Bumper at his ass (or her ass). A well timed deke can lead to a breakaway or at least an odd man rush. However, do not deke when it is unnecessary. That will lead to a turnover or worse. Performing a deke with a grinder or defensive defensemen is usually not a good idea.
I said there were 10 but I ran out of ideas. Sue me.
UPDATE: From duff and wilsmith.
10. Do Not Go Coast to Coast… At All.
Defenders should not be carrying the puck coast to coast. Make the pass to an open lead man. Try to not make the forwards curl at the blue line.
Head-man the puck!
It drives me nuts when defenseman or some slow forward tries to skate it out. Look up ice, everyone who plays forward leaves the zone as soon as the D get possession, so get it up there while they have a chance at an odd-man rush.
I always center and end up with the puck in our own slot a lot, then just turn it up the boards to one of the wingers. It almost always creates something because opposing teams over-commit in the offensive zone.
