A common list of rules are followed whenever there is a conflict in observing halakha:

1. Weightier matters of the Torah are Justice, Faithfulness, and Mercy
2. What is written takes precedence over what is not written.
3. Explicit commandments take precedence over implied commandments.
4. Positive "thou shall" commandments take precedence over negative "thou shall not" commandments.
5. No commandment looses its peshat (literal interpretation).
6. Peshat (literal) interpretations take precedence over remez (hint) interpretations.
7. Remez (hint) interpretations take precedence over drash (drawing out) interpretations.
8. Drash (drawing out) interpretations take precedence over sod (secret) interpretations.

• Discussion: Weightier and Lesser Matters, A Guide to Torah Observance