I have come to believe in the saying: "Youth is Wasted on the Young".
pnelson - Married or not, self worth (be it in looks, self-confidence or security) ALWAYS matter, IMO.
You ask, "what methods do you use to feel good about yourself?" and I have been pondering that question for a bit. The immediate answer that comes to my mind is my DH, he is always showing me and telling me how much he appreciates me, and over the years he has done a lot to boost my self-esteem. That helps alot, to have a supporting spouse. But there has to be more to it. Something has to come from within yourself.
We have all been guilty of playing down a compliment received. Someone says something nice about us and we deny it. Could be because of humility or because we really don't believe we deserve the compliment. However, we do!
Our lives are so full of doing things for others between work and family, that we NEED to take time out for ourselves. Treat yourself to a new outfit, hair style or something materialistic (sexy underwear does it for me). Take time out and read a book, escape to the beach or park for some alone time. Spend special time with your spouse.
I believe we also go through cycles of security and insecurity. I think the most important thing to do, however, is in private conversation with oneself, always talk UP about yourself. I try to privately praise myself for something everyday. Sounds silly maybe.... but it works for me. Hope you find something that works for you.