be more friendly

I’m shy and usually feel too like everyone thinks I’m really ugly and boring and they just don’t want to know me. Sometimes I can force myself to go and chat to people and make an effort as I have done more recently and it’s not that bad!
However saying that, a lot of people tend to think that I’m really stuck-up (what?) and posh (I wish) so apparently I intimidate people. Already I’m really shy, and then on top of that I have had many people tell me that when they first met me they thought I was so conceited and pretentious. It so isn’t good – I mean I can perhaps change my attitude but not my face.
Anyway, I’m starting a new uni in September and want to make sure that I’m as friendly as possible. I’m not that bad once you actually get to know me – at least I think I’m not.