We played a prefixes domino in class the other day and I promised to give you a list of all the possible words you could create with the prefixes given in that game. So, here you are (click).
Now it's time to revise the grammar related to this matter. Have a look at the following documents:
You should also pay attention to the pronunciation of prefixes since many of them vary from the Spanish pronunciation. You can watch the following video where you have some of the most common prefixes pronounced.
And if you want practice, here you are some very good links with exercises: