Or you'll fall for anything. If you do not have values, you never have good relationships. You must know who you are, what you believe in, and what you want in relationship.
Know who you are-You are who you are. You have essentially been this person your entire life. You are NOT what you do for a living. That is simply how you make money. You are a person with thoughts, dreams, hopes, and fears. If you really don't know who you are, you should sit down and write out a description of yourself. You can include your physical attributes, but that is only part of who you are. Write down all the things that are important to you, in any order. Don't leave anything out, even things you may consider to be flaws or faults. Once you have a better grasp on who you are, you can get on to having meaningful relationships.
Know What You Believe In - Everybody believes in something. I'm not talking about religious beliefs, although that is a big part of who some people are. I'm talking about the things you feel passionately about. Do you feel strongly about politics? religion? sex? West Australian hummingbirds? sports? raising children? Whatever you feel strongly about shapes who you are, and becomes your values system.
Know What You Want - If you are looking for a particular type of relationship, or a particular type of person, DO NOT settle for anything less. If you are looking for a purely physical, short-term situation, and you settle down with someone for a long-term committed relationship, you will end up feeling trapped and it will ultimately end badly. On the other hand, if you're looking for a long-term commitment, and you hook up with someone for a one-night stand, you will likely end up feeling empty and dirty. If you're looking for someone outgoing and personable, and you are with someone who is very shy and reserved, you are not going to be very happy, either.
It always comes back to communication, especially with yourself. You must know who you are, what you believe in, and what you want. Otherwise, you not be happy in any relationship.