Tip 1. You cannot go wrong with this one.
If you are nice to your partner, teammates, and opponents, you will almost ALWAYS do better than if you are grumpy, mean, or whatever other perjorative term you want to use here. Of course, the problem is that being nice is easier said than done in some cases. You might be mildly grumpy at partner for a perceived error in bidding or defense, at your teammates for missing a slam or misdefending, at your opponents for who knows what, etc.

Recommendation: Just LET IT GO, be nice, and especially be nice if you have to call the director because of a supposed violation of the Laws by the opponents.

AND, if your opponents are obviously being NOT nice to you, in a way that really interferes with your enjoyment of the game, call the DIRECTOR.

Tip 2. Adopt new conventions gradually (and only 1 or 2 at the same time). Many bridge authorities claim that quite a few points are lost by the misuse of new conventions, quite likely much more than are gained by the proper use (a claim that cannot be proved, but probably true). So, do not adopt a new convention just because it seems to solve a problem. Wait until you thoroughly understand it, know how to handle interference, AND are reasonably sure that you (AND your partner!) can remember it! (I know, forgetting it once and getting a perfect zero helps here.) It certainly makes sense to practice a new convention at the club before trying it out at tournaments, as tournament directors are NOT impressed by pairs that forget their agreements, and you might be subject to some type of penalty, especially if you forget twice.

Now, having said the above, I am going to contradict the above! At the club level, Experiment! Be quick to try something out (perhaps even if you do not fully understand the convention), keep some kind of record, and see how the convention works for you. The experience you gain (assuming the situations for the convention come up) will let you evaluate the convention. If you get NO experience at the club (the convention NEVER comes up), you should be reluctant to adopt the convention for tournament play.

In summary: Conventions that you use at tournaments should be conventions that have come up for you at the club, and you are comfortable with the convention. There are some exceptions. You should probably learn DOPI (and DEPO?) ASAP, even though it may be years before it comes up. (In 9 years, DOPI has come up once for me, and partner FORGOT). Some conventions such as lebensohl, new minor forcing (NMF), and fourth suit forcing (FSF) should be be high on your priority list to study, even if you do not plan to adopt the convention immediately.