Thanks Frug!
A couple of things that I would like to add that are more on the strategy side:
Route Running: If someone on your team has the ball and has 1 or more enemies closing in on them, it is almost always better to run away from your teammate and try to move to open space. This gives them someone to pass to. It is very frustrating when your own team runs straight towards you (and the enemy) when they should be running away and looking for a pass. This is basically what Turboflex just said, but it really needs to be stressed.
I personally don't like it when someone on my team runs with me as a guard, unless we are very close to enemy goal. Again, I would prefer that they move away into open space and be ready for a pass.
Route running also applies to the ball carrier. Sometimes you want to run sideways or away from the goal you want to score on. You can sometimes draw several defenders your way while someone runs right down the middle. If you use your Outfit View key (noob alert: which I didn't know existed until a week ago) you will be able to see when to turn and throw. After you throw you start back up field as the defenders now turn and all chase the ball. Now you are open for a pass.
Kicking: If you have a weapon that does not have an down attack, you can also use a down block.
Goalies need to be aware that if you aren't that good at kicking or miss the first kick, it is usually quicker to pass the ball. With 3 good passes the ball can be 3/4 of the way down field on the Rageball Stadium map and still controlled by your team. This does assume that people are in position and expecting the ball.
Catching: You can use F to catch the ball, as has been stated. What most people do not realize is that a lot of times the goalie will throw the ball down at their feet so they can kick it. If they throw it close enough you can press F and it will pull the ball out of the goal-box. Most goalies will realize what to correct after this happens once or twice, but it is still very useful. Remember, that any moving/bouncing ball can be picked up with F. This is going to come into play more now on the maps with hills. The ball rolling downhill can get away from you quickly. Use F to grab it before it gets too far.
Rageball is loads of fun especially when there are two good teams that are working together. It sucks when it denigrates to TDM and dueling.
Here's a link to the "Official" Rageball guide:
http://forum.c-rpg.net/index.php/topic,25571.0.html