Side hustles, like everything else in life, have rules.

Rules. You know. Those things you SHOULD do but don't always want to.

When your teachers told you that “you're not cheating anyone but yourself” they were right.
So think of these suggestions as ideas you have to follow.  Like rules.

The following includes rules, suggestions, tips, and generally sound advice.

1. Never let your side hustle interfere with your real job. Your day job comes first.

2. You have to pay taxes. Assuming of course your hustle turns a profit.

3. Know why your doing this side hustle to begin with, I.E. pay off specific debt, better funded Roth IRA etc.

4. Boundaries. Your side hustle has its place. Keep it there.

5. Your side hustle has to be realistic.

6. Keep it legal. If your hustle requires permits or licenses get them.

7. Learn from the mistakes of others. If someone tells you something there's a fine line between wisely taking it with a grain of salt and ignoring sage advice.
Know the difference and learn from it.

8. Don't go into debt to start your side hustle. The point of a side hustle is to make money.

9. Know up front the financial expectations.
 A part-time job as a side hustle tells you exactly how per hour your making. 
Everything else is everything else. 
Know what to expect. 
If your side hustle doesn't measure up find out why and what to expect going forward.

10. Only spend money if your really certain it will make you more money back.

11. Be prepared to tighten up your calendar.
A full-time job and a side hustle takes some real time management skills.

12. Don't let your side hustle interfere with your personal relationships.
 Moneys important.
 So is family.

13. Don't start a side hustle outside your circle of competence. 
You can always learn more but don't advertise yourself as something your not. 
That being said, always learn new skills.

14. Exploit any competitive advantage you may have over your competitors. 
You can possibly charge more than others with better results.

15. Don't badmouth the competition.
 It makes you look like you can't compete. If however, the competition trashes you and are outright lying about you don't just ignore it. 
Confront it immediately and directly.

16. Have goals. 
 Without goals your side hustle is little more than a glorified hobby.

17. Don't take jobs that don't pay anything just to get your foot in the door. 
You'll soon develop a reputation as a low-cost provider of your services and attract exactly the wrong type of customers.

Rules are just things you have no choice but to do.
Suggestions are things you should do.
Tips of the side hustle trade are those things your only cheating yourself by not doing.
Make your teacher proud.
 Do them anyway if they apply to your situation.

Don't let these rules sidetrack you from starting/continuing a side hustle if theres decent money involved.
The entire point of a good side hustle, at least in most cases, is your hustle to help you reach your financial goals much faster than you ever thought you could.