Just do it.
Dry diving is not as difficult as people make it out to be.
Even when you get too much air in your feet and get hung upside-down it is really easy to correct.
Specific tips:
1. "15 FOOT SQUEEZE" - Start by dumping all of the air out of your dry suit at the surface. Descend normally. You will start to feel a squeeze. When you get to about 15-20 feet, remember what it feels like. That's the amount of squeeze you want to maintain during the dive. As you get deeper, start adding air to your dry suit in bursts to maintain the feeling you had at 15-20 feet.
2. For fun, descend without adding air and see how painful the squeeze can get.
3. If you add too much air to your dry suit, you will have a big bubble of air that really throws of your trim.
4. Use the dry suit inflator to regulate the squeeze. Use the BC inflator to regulate your depth. Don't make it more complicated that it has to be. Some people (like PADI) will tell you to use your dry suit as your BC, but see #3 above.
Have fun!