DCEric saidAlthough I didn't follow it word for word, this book helped me a lot. Someone on here recommended it to me.
Buy this book and read it. It's got some workout plans in it pre-made, that you can start before you finish reading it.
If not that, go onto bodybuilding.com and find a beginners workout.
Your question is extremely broad. It sounds like you want to make the upper body muscles bigger/more defined. I'm guessing because they are sexier.
Because of the broadness of your question, I'm guessing that you aren't working hard enough or consistently enough to see a change. So if you find any workout that you can do hard enough and consistent enough, you should see some positive changes. It probably doesn't matter much which workout you do.
Also, don't focus on just those muscles. If you do, you will cause all kinds of problems for your self over the next 5 years, because of the imbalances you will create.
Working on your back and your legs is extremely important. Also, working your legs and back will boost your testosterone (naturally), which will help your body make all of your muscles grow (including your biceps, pecs, shoulders, triceps and deltoids).