Personally, I first had to decide that I wanted to love myself, even if I didn't at the time, even if I felt like and believed in much of my mind that I did not deserve love, that I hated myself, that I was for the most part a piece of crap. Part of me did believe that I deserved love - why else would I want love so badly? why else would I want to deserve love so badly? Eventually I came to the realization that the negative thoughts, the self-hatred, were, quite simply, pointless. They weren't taking me anywhere I could possibly want to be. So I said, I am going to do something that makes the most ultimate sense, the has an ultimate purpose, that ultimately inspires me and brings me joy and happiness... because that seems to be the only desirable direction to go, at the end of all things. Now, of course, I knew that my mind would keep rationalizing and rationalizing at these fears, the self-hatred, and tell me it was somehow justified. And yet I did not want to feel that way, period. I thought, even if I deserved to die, even if my life was not worth the trouble, wouldn't it make more sense to just kill myself rather than agonizing over it first? Because it wasn't really about whether my life was worth the trouble, but whether agonizing over it was... so I finally said, okay, I am going to try an experiment and see if I can love myself, and see what loving myself is like, before drawing the ultimate conclusion as to whether or not I deserved it... because once you experience that deep, abiding, unconditional and consciously chosen love of yourself for yourself, you may just realize that it is indeed what you want and what you deserve.
Give yourself a chance. Look yourself in the mirror a thousand times and say to yourself that you are beautiful and you deserve love and you love yourself. Don't require that you believe in it yet; only require that you give yourself a chance to feel what it's like to deserve love.