One of the most important few ways that you can improve your life (along whatever dimensions are important to you) is to be selective about who you spend time with.
If you want to stop drinking, hang out with sober people. If you want to get in shape, hang out with people who work out and are active. If you want to be a better eater, hang out with people who eat well. If you want to be more spiritual, hang out with spiritual people.
"You are the average of the five people you spend the most amount of time with."
"Show me your friends, and I will show you your future."
"He that walketh with wise men shall be wise: but a companion of fools shall be destoyed", Proverbs 13:20, Solomon