Pick a good knife. Don't settle for a cheap molded rip-offs. Get a good titanium blade with strong straps. I would recommend a knife with blunt tip for safety reasons. Get a good flashlight. I saw people using two flashlight system. One is a very big but powerful wide beam light and second one is a smaller type also powerful but not as wide. I only use a smaller one. It gives me greater chance to go around and doesn't slow me down. Now attach couple of climbing carabiners to you BCU. In high waves or when waiting for your turn to enter the diving platform it's much easier to get attached to the rope thrown from the dive boat. Or if you are just resting next to a buoy and you don't want to drift away or if you want to attach yourself to a buddy in a poor visibility. Get your self couple of glow sticks or a Krill light and also attach it to your BCU. Krill light is better because you can turn it on or off but it requires practice (I flooded mine once). Try sticking to white lights for a true color views underwater. Princeton Tec Aqua Strobe is strobe light, water tight down to 2000 feet. It will blind you underwater but when you surface it's an excellent locator for a night time. For my on-board kit my bag has load of rubber straps for my mask and fins, rubber bands, duct tape, o-ring and sealants, ropes plus set of small wrenches and Swiss Army Multi Tool. Pony bottles are great back up systems but they do cost a lot. But they should NEVER be used or calculated into your diving plans. You should plan such that you still have air left in your tank when you surface and pony tank would be used in emergency situations only. You place pony tank on your BCU around your chest flat usually. My gauges (air, navigation, compass, dive computer) are electronic so I carry a spare battery but I also strap magnetic compass to my wrist just in case. Now all the strobes, hoses and things have a tendency to go into different directions when underwater. Try keeping everything tight and organized. <br><br>But all the about gear (except for pony bottle) will increase your survival chance mostly on the water. Under you are still forced to make sound and reasonable decisions. You have to maintain your equipment and observe all the safety rules. Listen in class and ask questions, go over thing you are unclear about. You will get better with time. Underwater your life depends on your gear so take care of it. And be friendly and cautious of other divers and aware of your surroundings... Never had a bad experience when diving and that's probably because it is the only thing in my life that I did by the numbers. I never tried to skip a step. As you get more experienced you will see you can push yourself little further and go places where you couldn't at the beginning.<br>