Here are some basic bidding errors that will annoy your partner!
1. With 12 or more points, do not make an opening bid.
2. If you do open, don't rebid if partner responds with a new suit.
3. Do not respond even if you have 5 or more points.
4. Respond at the 2 level with fewer than 10 points.
5. Don't try to find a game contract if partner jump bids in a new suit.
6. Respond in NT, even if you have a biddable 4 card major.
7. Rebid after a 1NT opening whether asked by partner or not.
8. Rebid at the 3 level or reverse even if you have less than 16 points.
9. Overcall with fewer than 5 cards in that suit or with no honours.
10. Change partners overcalled suit if you are weak.
11. Overcall in NT’s with fewer than 16 points and 2 stops.
12. Open a Weak 2 when vulnerable or if you have a 4 card major.
13. If everyone is bidding, go for a game contract.