There are several synonyms for the phrase "stick to," with each having a slightly different connotation. The most commonly used synonym is "adhere to," which means to stay true to or follow closely. Another synonym is "abide by," which implies a sense of obligation or duty to comply with a rule or law. "Follow" is a more general synonym that can be used in a broader sense and doesn't necessarily imply a strict adherence. "Observe" is another synonym that connotes following a set of guidelines or rules. Finally, "maintain" can also be used as a synonym, indicating a commitment to a certain course of action or belief.