Your word is the most important thing that you have to offer. Don’t take it lightly. Always consider if you can fulfill a promise. Also, It’s okay to say no (unless it’s on your daughter’s wedding day).
2. Don’t involve yourself in other people’s personal lives.
Gossiping or giving advice on personal matters should be frowned upon. Someone’s personal life is exactly that – it’s personal and privacy must be respected. When Connie and Carlo have a fight at the dinner table, Sonny tries to intervene only to be hushed by Mrs. Corleone, “Sonny, don’t get involved.” – Carmela Corleone
3. Family is the most important thing in life.
Blood is thicker than water. “A man who doesn’t spend time with his family can never be a real man.” – Don Vito Corleone
4. Don’t go against your family.
Learn from Fredo Corleone. No matter how much you dislike your family, they’re still your family. Out of respect, do not go against your own blood, unless you’re prepared to suffer the consequences. “Fredo you’re my older brother, and I love you. But don’t you ever go against the family again. Ever.” – Michael Corleone.
5. Don’t act on emotion.
Before taking action, considered all of the possible outcomes of your action. Think wisely and diplomatically. Emotional outbursts and being predictable eventually lead to Santino “Sonny” Corleone's downfall. Don’t ever become predictable. “Never hate your enemies. It affects your judgment.” – Michael Corleone.
6. Keep your friends close, but your enemies closer.
Keep a watchful eye on your enemies and play life’s “game of chess” with precision, dedication, and tact. Hold your ground and never burn bridges (no matter how much you might dislike someone). Especially in public. When Michael Corleone was bullied by Senator Pat Geary he simply replied “My offer is this…nothing.” He kept Mr. Geary in his circle, and eventually landed him in his pocket.
7. Establish friendships out of respect, business, and trust.
You can't choose family, but you can choose your friends. Consider the benefits and disadvantages certain friendship can bring. Weigh the pros and cons and choose carefully. “Friendship is everything. Friendship is more than talent. It is more than the government. It is almost the equal of family.” – Don Vito Corleone.
8. Keep your business private; only discuss it amongst family members.
It’s best you keep business private to outsiders. Don’t discuss your personal or family business to strangers. You never know who will use this information in their own favor or for their own personal gains. “Don’t ask me about my business!” – Michael Corleone
9. Build a powerful community.
By helping others, you will receive help as well. You will also receive respect. Don Vito Corleone built a powerful empire by building a strong community. He helped his local neighbors and friends and established a strong reputation. “Someday, and that day may never come, I’ll call upon you to do a service for me.” – Don Vito Corleone.
10. Don’t take things too personal.
Sometimes, you simply need to remember that, “it’s not personal, it’s business.” – Michael Corleone