1) Don't crash. If you want to take chances, then do it at altitude until you are totally comfortable with the plane and you are absolutely confident in it's reliability.

2) DO NOT clean your planes with paper towels. They scratch the hell out of your finish because they are very abrasive. You won't notice it for a while, but your finish will become dull after a season and keep getting worse. Gently brush sand, dirt and dust off the plane before you start using a rag to clean it. Those things will really tear up your finish. Use a soft, absorbant cotton rag for cleaning. I use baby diapers. Windex is fine, but buy bargain brands.

3) ALWAYS perform maintanance on your planes when you go home. Don't keep flying a plane that has things going wrong with it even if "it's ok for now." That covering will be harder to iron down if you let it stay loose very long.

4) DO NOT perform field repairs. They're ugly, sub-standard and really hard to make right. Mostly they are done because the person doesn't have the discipline to stop flying that plane for the day. If you make repairs in your shop, you can keep your plane in farily new condition. Take two planes to the field so if one is broken you can keep flying.

5) Be nice to your planes.

6) Do a pre-pre-flight inspection at home where you won't be distracted by your buddies at the field. Also this gives you time to thoroughly go over your plane and see if anything needs maintanance. You may have meant to change something and forgot.

7) More, but that's all I can think of off the top of my head.