Practice rescues, not just rolling, all kinds of rescues. Everyone likes to roll, but how many different self rescues, and assisted rescues do you know? How often do you practice them? Can you do them in rough water - which incidentally is where you are going to need to do them! - Make it fun. Twice a year I try and get a group of friends to get together and do them. If I cant find people to practice with it do it alone. You want a challenge? Try getting someone with a dislocated shoulder back into a boat. Have you ever used a stirrup? Got a paddle float? Great. Now use it.