Yesterday's chapter in Proverbs had several verses that talked about fools. Today's chapter has several verses that talk about friends and how they help make you a better person (and I think you can logically conclude keep you from being a "fool").
5 Better is open rebuke
Than love that is concealed.
6 Faithful are the wounds of a friend,
But deceitful are the kisses of an enemy.
So a man’s counsel is sweet to his friend.
We all need friends in our lives who we will allow to be totally honest with us and tell us when we are messing up our lives. To have that kind of friend you have to be that kind of friend. You must be able to tell your friend the truth when he needs correction. I suppose we all would prefer a kind and gentle correction, but if correcting with kindness doesn't work we sometimes have to be more forceful. (look again at vs. 5-6)
If you don't have an iron sharpening iron relationship with anyone, let me encourage you to pray and ask God to send someone your way (and don't forget that you must be willing to be that kind of friend yourself.)