I dunno about perfect, but these are just some traits that I really value/like:
-Kindness and open-mindedness. For a lot of my life, I've only interacted with people who have been pretty cruel/insensitive. After having met people who are the opposite, I never want to go back. These qualities are a requirement for me, not just in a partner but in any friend or anyone I associate with.
-Defined interests. I've met people who don't really seem to have hobbies. I don't care how boring or simple the hobbies may be, I like people who know what they like, who actually have interests. People who are passionate about things, and not just floating through life without really enjoying it.
-Loyalty and trust. This is a big one for me. I don't have many friends, but the ones I do, I am very close to. Those who are a part of my inner circle describe a relationship with me as being "intense." I don't open up to others easily, but once I have, that's a special kind of closeness.
-Upbringing and high standards. I was brought up to always be respectful and courteous to others. Additionally, having high standards in terms of many sectors of life (whether it's for food, material possessions, people, relationships etc.). I hold myself to high standards and am naturally attracted to those who have high standards as well.
Those are the most important things in terms of personality/nature. Physically...well I have a thing for short hair. My ideal partner would have hair that grows quickly enough that if she cut it short, it could grow back to medium-longerish length. I also kind of prefer brunettes.