The constant Mitzvos:
The Poskim  enumerated a list of Mitzvos that one has the ability to constantly fulfill throughout the day being that they are not limited to any specific time, place or action.
- Belief in Hashem
- Not to believe in the existence of any other G-d.
- The unity of Hashem
- Love of Hashem
- Fear of Hashem
- Not to swerve after one’s heart and eyes.
To Purchase this Sefer:
 Sefer Hachinuch in his introduction [brought in Biur Halacha 1]; Chayeh Adam Klal 1/5; The Sefer Chareidim [introduction] lists 6 constant positive commands and 7 constant negative commands