The Top Ten Things Upright Bass Players ignore at their peril

This list is in no particular order. Updated from an original concept by Bob Gollihur.

1. Bridge Creep - As we continually tune up our strings, those strings try to drag the bridge towards the fingerboard. This can result in poor acoustic sound quality (as feet lose firm contact with the bass table), a decline in pickup sound quality, and a permanently warped and frequently falling bridge. Keep an eye on it, your bridge should be perfectly perpendicular (a 90 degree angle) to the bass' top; usually the side facing the tailpiece is straight, and the fingerboard side is curved.
2. Strings - Listen to them, and listen to other players. New strings are being developed all the time, and there's dozens of variations out there. They can often really improve or otherwise change your sound and playability for the better. I'm not suggesting you become rabid about changes, and become a charter member of the "String of the Month Club" - just keep your ear to the ground and to your bass. The decline of quality sound of even our favorites is usually gradual and not always so obvious... until you put a new set on!
3. "I already know how to play" - Some people keep their heads down and believe their ways are the best ways. They don't stick their heads out of their cubicles to find out what is going on in the world. Those can often be people with no prospect for advancement, and more aggressive players are passing them by. There is no shame in being confident in your knowledge, but it can be foolish not to add to it. We don't have to use it if it doesn't apply, but should not be threatened by something different. Be joyful in valuing ALL types of music, and not afraid to incorporate what we can appreciate into our own personal bag of tricks.
4. Learning Amplification - How many hours have you spent learning bass and honing your skills as a player - now, compare it to your time actually learning about amplification. All your musical skills, top-notch bass and strings, and the care you put into your technique to create a beautiful tone? It can all go to waste if it's funneled through a system to which little attention was paid. Spend the time necessary to become knowledgeable about pickups, preamps, amps... all the pieces that deliver your sound (or don't!) Hey, we've got a free E-Book that can help!
5. Trying New Stuff - If you usually say "I Don't Like that pickup, those strings, that bass, that amp... " within the first ten seconds, you're not giving it/them a real chance (or I could say that you're being "closed-minded" if I were rude). Different is not always bad. I know I'm not smart enough to make a truly educated judgment in such a short time, give innovation a chance!
6. "This is as good as it gets." I've seen many players who have concluded that they can't bow their bass well; those who get uneven sound from their bass, etc. Very often we haven't spent enough time to determine that it's a bow with substandard or old hair, lousy rosin, bad strings or setup, etc., that is at fault. Don't settle on this or other bass issues without determining potential issues that may be limiting you.
7. Focusing on only ourselves - It's easy to get caught up in our own performance. Don't miss out on what the other players are doing and how your sound, note choices, attack, dynamics... EVERYTHING fits in with what the band is trying to achieve.
8. Relying on Amplification. If you practice your acoustic bass through an amplifier, stop. If you haven't played a gig totally acoustically in a long time, do so. A good acoustic sound is the root of a good amplified sound. Don't let yourself get lazy and rely on amplifiers, dig in! Real tone comes from your hands.
9. Believing everything you read on the net. The net has given an equal voice to both the most knowledgeable as well as the most ignorant. Consider, but don't give immediate credence to what you read there. Consider the background and perspective of the author. My first pie in the face goes back several years, resulting from listening to a guy touting a bass string as "the best I've ever played." He was being honest, but it was only the second bass string he'd ever played.
   
10. Forgetting how cool we are. This one is only semi-serious, but there's a truth nugget here: have you ever noticed that when an advertiser wants to communicate "cool" in their commercials, they'll have upright bass players in the ad or at least have it dominate the background music? Don't forget how cool we are - but then again, don't flaunt it. It only makes non-URB players jealous.