Prepare for your classes as you would any dive. Be well rested, no alcohol, hydrate. Also be aware that you need to understand that you are a student. You are learning something new. Be patient, take your time and ask questions. Also, you are not in a competition with your classmates. Just because someone else "get's it" and you don't does not matter. Some folks can just jump in and take off. Others, and I think many, need to take baby steps to get to the point of some comfort. One of my favorite Divemasters says it plain and simple. "Take if very very slow". Enjoy and Congratulations on your new adventure. Sue