Your an average looking brother. You don't look like a jock nor a nerd. The first pic had a little swagger to it, the second looked very stiff and nerdy.
1.You need to develop an identity and a style. Do you have one? What do you like to do? What are you hobbies and interest? You need reflect that in your style. I'm a graphic artist, I tend to go kinda preppy/kanye on occasion. Or nerd glasses witty tee shirts and converse every now and then. But when I go out, its nice button downs, designer jeans and nice shoes.
2. Hit the gym.
3. Confidence will win the day when looks won't. I know this guy who looks like a chiseled black Ralph Lauren model, but he has Zero confidence and is awkward around women. All the sisters around here thought he was gay because he was so pretty and awkward around them. He finally found a pretty and awkward girl of his own and now they hit it off. They look like a magazine layout. But for years he couldnt get laid to save his life except by chicks that were way below him in looks.
Your young man. you got time to grow into yourself, women are still gonna be there, so just take your time and do your thing. Keep putting yourself out there and keep learning. Good luck.