Most club racing uses the Low Point System from Appendix A of the Racing Rules of Sailing: a boat scores points equal to its finishing place — 1 for first, 2 for second — and the lowest total wins. A boat that did not start, did not finish or was disqualified scores the number of boats entered in the series plus one.
Longer series allow discards: once enough races have been sailed, each boat’s worst score is excluded. The sailing instructions say how many races it takes to earn a discard.
Handicap fleets correct each boat’s elapsed time with its rating before places are given, so a slow boat sailed well can beat a fast boat sailed badly. The points work the same way after that.