If you're interested in your score, then you need to know that playing IMPs (such as in most Swiss pairs and teams events) is different to playing normal matchpoint-scored duplicate sessions. Here is a summary of tactics for Swiss pairs/teams (ie IMP scoring) summarised from several internet sources:
- Make your contract. Play as safe as possible to make your contract and don't play for overtricks. Overtricks are not as important as in matchpoints where they are everything. If you’re in the right spot, it usually works in your favor. Trust your bidding system.
- Stretch to bid a game. If vulnerable, 40% games should be bid, such as 3NT with 24 points. If not vulnerable, 50%. You’ll pick up ten imps for a vulnerable game the field didn’t bid (+620 – 170 = +450 = +10 imps), whereas you lose only six if you fail in a game they didn’t bid (-100 -140 = -240 = -6 imps). Go for it.
- Don’t double their part scores, unless you can see them down two in your own hand. And this means you have a fistful of trump tricks. Don’t count on your partner for tricks or double strictly on high-card points.
- Your competitive bidding should be more constructive than at matchpoints. Don't make wild, preemptive bids just because you have 6+ cards in one suit. Don’t go down for (postcode) numbers.
- Play your safest contract. If you have a better fit in a minor, play that, especially partscore. Make whatever you bid. +110 is only one imp worse than +140. This also applies to games and slams.
- Don’t stretch to bid slams. Bid only slams that are at least 75%
- Don't make a risky bid or play because you think you are down in a match. You never can tell what’s happening at the other table.
- Don’t make a confusing bid that partner may pass (you thought it was forcing) or that shows extra values that you don't have.
- Take out insurance. There are sometimes wild hands with lots of distribution, doubles fits and long suits. where both sides can make game. It is usually right to bid one more, as it’s hard to tell if they are going down.
- Take a chance to beat a contract. Sometimes you give up an overtrick (only - 1 IMP), but If your bold play beats it, you are well ahead.
And remember, if a hand’s hard for you, it's hard for everyone else. This guiding principle will help you on several of the points already listed.