DO: Maintain close ties with those friends that are important to you outside of your relationship.
We see this rule broken all the time. A person gets into a relationship, cuts off contact with those close to them, and then ultimately ends up unhappy. You need to find a balance and maintain contact with everyone in your life in order to sustain a long-term relationship. Don't lose yourself once you get into a relationship. It's vital that you have a strong support group surrounding you that extends beyond just one person.