Don't worry, i often used to feel second best and left out of group activities and it made me very shy.
I found the best way to cope was just to be myself and as I became more comfortable about who I was, despite the fact that i was not one of the more popular people at school, it made me more confident and sociable and I got to know people better and became more involved in groups.
I'm sure you will have no problem in getting a boyfriend, different lads look for different things in girls but as long as you're confident in yourself you'll be more attractive and then you'll find the right guy for you, there's somebody for everyone.
Just don't give up, you may feel second best but many people can feel this way and it isnt usually the case, we're all special in our own way.
Hope this helps x