One thing a LOT of newbies do (and i did it too - still do) is making their make-or-break move first.
If it works, then that's great, but if it doesn't, you could leave the opponent open to score, or get the ball off your guy.

I know new players have a lot to take in, and that sometimes your excitement will get the best of you, but i think you should try to compose yourself and do your safe moves first.

The reason this is so important is that your turn ends as soon as you fail a dodge, ball pickup attempt, one of your players falls over in a block, or you try a pass which lands on the ground.

1) stand up guys on the ground if they're not going to blitz or dodge away.
2) Make any moves which don't require any dice rolls. (this includes setting up assists)
3) Now you have to weigh up between your important actions, and your fairly safe actions. Eg. you might have two actions available to you: a 2dice block using a guy with block, or a one dice blitz on the ball carrier. You will need to learn where to draw the line (and you will in time).
4) consolidation actions. Eg. If you knocked the ball free of it's previous carrier, you might want to put some tackle zones on it if you can. This will make it harder for the opponent to pick it up.
5) fairly risky moves. (this inludes one dice blocks, 2+ dodges etc which aren't very important).
6) rediculous moves (eg 2dice against blocks, 5+(or worse) dodges etc).
I actually think that a lot of the time you shouldn't eve try these. You're usually better off having your guy prevent the opponent's player from moving freely.