This is the only picture I have of him right now.
He's the guy closest to the camera.
My brother spends inordinate amounts of time perfecting his image; he takes great pride in his hair, which he systematically straightens every night after a shower. (To the best of my knowledge, he still does it - I'm not living at home right now.) Personally, I think this is a ridiculous ritual which is pointless and time-consuming. Nonetheless, I'm different to him. Most would look at me and say "doesn't care about his image". People look at him and say "good fashion sense, takes care of his appearance etc.". He's got a wide social network; he's never short for people with whom he can chill or do things, like party or watch a film. Academically, he's intelligent, but only if he works hard, a bit like me, except that I'm more intellectual and theoretical than he is; I'll spend my time posting on forums, whereas he'll spend his time with friends. Only when he's entirely run out of options for socialising, or if he's waiting for his friend(s) to arrive does he sit down, slouch around and watch TV. He gets very easily bored by philosophical or theoretical conversation, which my father and I frequently engage in (it's not just him either; it's my sister and mother too, although due to my mother's obvious maturity levels, she will be happy to talk about such things as the philosophy of art).
My brother enjoys parties, but he often prefers active outdoor activities. Often he'll be playing with fire by throwing bottles of flammable shit into a barrel or making mounds of dirt to do cool bike stunts on; essentially partaking in "boys' stuff". Although he's grown out of it a bit now, he'll frequently go through periods of interest in building or making something. He generally prefers to socialise though; I get the feeling he's far more partial to gatherings of close friends than of huge, wild parties. In any case, boredom is his worst enemy, it really is. So when I'm at home, he's very rarely around, and when he is, he's intent on playing on the Xbox, or playing Risk or entertaining his mind with something where he's "doing" something; keeping his entertainment levels up and boredom levels down.
I always tell people when they ask me to describe him all this, plus how I compare with him. I always say "you'd like him a lot more than me. I'm an aggressive, moody bastard, he's a likeable, easygoing, entertaining guy". He's very socially aware, both of people and of etiquette in the social arena (e.g. he had a massive problem with my arguing a point with him at someone else's house). He's more attuned and sensitive to people's feelings and desires than I am; I will shout my point regardless, whereas he will often offer up a different interpretation, which is often highly insightful. For this, I commend him. As I said, academically he's intelligent when he works, but socially, he's a master of his class. Truly.
Ask me some questions on him if needs be. Obviously I may not be able to answer those that are to do with how he thinks, because I can only guess.