Maybe try out some role-playing, or invest in some fun new lingerie or marital aids. Generally men are visually oriented. They become stimulated just seeing you naked, or dressed pretty. So get out of those ugly sweat pants. If you've put on a few pounds quit sweating it and dress nice.
Many men prefer a voluptuous woman, get over being self-conscious.
If you don't feel good about yourself, do some things to help you feel good, he will follow you in turn. Be light hearted. One day I was full of mischief and decided to surprise my husband. I went to the store and when I returned home, instead of just coming on into the house I knocked on the door and pretended I was a religious zealot and started preaching to him on how I could save his soul. We laughed and giggled, ended up having a grand ole' time.