These are great and wonderful Stoic principles to keep in mind. You could call them rules but in Stoicism there really are not rules per say.
Don’t be overheard complaining…even to yourself (Marcus)
Don’t put on airs about your self-improvement (Epictetus)
Don’t overindulge in eating or drinking (Musonius)
Don’t speak more than you listen (Zeno)
Don’t avoid difficulty (Seneca)
Don’t tie your identity to the clothes you wear, things you own (Cato)
Don’t conceal what you truly believe (Arius Didymus)
Don’t go along just to get along (Agrippinus)
Don’t be all about business (Marcus)
Don’t put off to tomorrow what can be finished today (Seneca)
Don’t shun people you disagree with (Seneca)
Don’t sleep the day away (Marcus)
Don’t neglect your friendships (Seneca)
Don’t waste time thinking you are going to live forever (all)
I got the above list from my friends at The Daily Stoic and thought they did a good job!