The options are:
- You are overestimating your own value. Either improve yourself or settle.
- You are not meeting enough men, and when you are around guys you like, you are not very approachable. If you think that *one* guy doesn't like you and it upsets you, get over it. Not everybody can like everybody. You need to make sure you meet new people often, that you look your best when you do, are approachable and sweet.
If you focus on looking your absolute best (diet and tone up, do your hair every day, the right make up and clothes), you are sweet and personable, you go out a lot and meet men in social settings (bars, parties, dinners) over several months and STILL don't get attention from the men you like, then yes, you need to lower your standards.
Of course keep in mind that young guys are often afraid to approach and aren't a correct estimate of your 'value'.