For a competition or a division, another option is to specify a start and end date for standings. This is useful if you want to have, say, two weeks of preliminary games that don't count for the standings. Another time this is useful is for an end-of-season tournament in the competition, if you don't want those games reflected in the standings.
To set a competition's standings start and end dates, go to Competitions and click on Edit next to the competition. Fill in the standings start and/or end dates and click on Save Changes to Competition. Of course, you can also set these dates when adding a new competition.
You can also set standings start and/or end dates at the division level by editing the division (Divisions > Edit Division). If division standings start and/or end dates have been set, they will override any settings for the division's competition.