I want to buff up, but how?

So the summer's coming up, I'll be at the beach a lot, but I'm pretty weedy. I'm 16 years old.Anyone know any good excercises for buffing up the upper body, purely for cosmetic effect?I'm currently doing 10 chin-ups (holding the last one for 5 seconds), 60 sit-ups(holding the last one for 10 seconds), and 20 push-ups (holding the last one for 10-20 seconds), every weeknight.Is this enough? And can anyone suggest any other workouts?
Answer:
1. ur 16 so u should b doin more.
try doin 60 sit ups each way.like regular.then 1 foot over to one side (like over ur other leg)then the other way so u work all of ur abs( b.c u have a left, rite and middle ab)then do 20 pushups in between those 60.
and also try runnin a lil..it'll tighten ur stomach..run around the neighborhood acouple times

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You shouldn't hold asnyhting just keep up the work plan but increase the amount every night by going untill you can't go anymore....I say that because if you keep pushing yourself then you'll get yourself looking really good for chicks like me that like a sexy body

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You have to workout, but also eat alot. When you bulk, you want to eat more calories than usual, not like when you cut weight, you want to eat less calories. Buy ON 100% Whey Protein, and drink it in the morning and after a workout.

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