Finding the right point between self-esteem and self-effacement is not easy. However, it's something you can master if you work hard on it. First of all I would like to mention 5 things to take in consideration if you want to reach the goal. (I'm still working on them).
2- Notice that people can flatter you the same way that they can criticise you.
3- Listen to other's opinions about you without identify yourself with them.
4- Only *you* can decide your own value, even if it's true or false to others.
5- Love yourself desperately without bragging; try to keep it in secret.
When you love yourself you accept everything about you and try to be better everyday. Of course there's no need to mention this to everybody. In fact some people believe that if you love yourself too much, you'll become egocentric... so keep it in secret.
There are so many books about establishing the perfect relationship with others (specially your lover) and that's ok until a certain point. Focusing too much on what you want to receive from your partner can be exhausting. You need to focus on covering your own needs and wishes because only *you* know exactly what you want... so no more expectations :) That's happiness.
Our society has taught us differently: You have to find someone that can fulfil your needs etc. I mean, of course this is something that comes naturally when you're in a relationship; you care about your partner and he/she cares about you (including needs and wishes) but they are not there to guess everything you want (or miss from your childhood). To me, the concept of the half-orange has been misunderstood. You don't need to be completed by other. You are a human being that can fulfil your own needs (with help accepted) enjoying life with the person you love at the same time; but you are your own half-orange.
It doesn't matter if you don't look like and actor or a top model. You need to find the special points about you. The points that nobody else has. I know it is difficult with all the media and advertising convincing us to be like somebody else. Don't let them decide who you are. Only you can decide that. They just want to sell things through stereotypes of beauty. Feel free to be yourself and to love yourself in a crazy way. I have just started.