Well I am doing OL but its much the same on Reproduction to be honest..
- PRACTICE PAST EXAM PAPERS (EVERYTHING THAT HAS COME UP ON REP. BOTH MALE AND FE-MALE)
- DRAW AND LABEL DIAGRAMS (REPEAT UNTIL IT GETS A BIT EASIER AND THEN TRY DRAWING AND LABELING DIAGRAMS WITHOUT LOOKING)
- LOOK AT SOME SHORT QUESTIONS ALSO AS REPRODUCTION (FOR OL ANYWAYS) APPEARS ALMOST EVERY YEAR.
I think if you're trying to study the male reproductive system in depth then stop. If you do exam questions like Jamie said you'll notice that the male questions asked are not very detailed. For a male you generally need to know how to draw the reprod system so yeah definitely practice that. Other than that you'll just need to know the function of each part, the primary and secondary characteristics , a cause and corrective measure for male infertility. What I find helps me is using record cards and quick, simple definitions eg;
Epididymis- sperm is stored and matures there.
And so on, keep saying it out loud when you write it and eventually try to say off a paragraph about the male reprod system without referring to notes. Hope this helps, good luck:)