I find that the company you keep breeds similarities in yourself. For example, if your friends with people who drink constantly, chances are you will drink as well.
I started a thread a while ago about surrounding yourself with people who are better than you- role models if you will. I think this works splendidly. I have a couple of financial bloggers who I consider role models and I've picked up lots of good habits from them. One of those financial bloggers also blogs about entrepreneurial issues and so I pick up those habits as well.
For me, a role model is a person that I consider more knowledgeable on a given topic and who I sponge information and habits from. Greatest thing around!
Here's a phenomenon I've noticed though: my generation (I'm 27) seems particularly resistant to role models. They would rather break through the proverbial wall with their fists than use the door. Anyone else notice this?