Keep your promises – A promise is a promise, when spoken fulfil it, try not to give excuse for not fulfilling because of something bigger has happened. When you honor your promise, and people will too, give you the respect that you need, works two ways.

When you really can't fulfil don't tell a lie to cover. Don't make a promise just to shy away, you know know people remembers. Don't promise unless you can fulfil. Put yourself in the shoe, you are expecting to have a meal certain people and last minute he tell you he has something on. Do you realize, we choose to do more important things first, so am I not that very important?

Respect people as people respect you. Once the trust is breached, you will have a hard time repairing, or even lose the friendship.