I'm an average sized guy....maybe slightly skinnier than average. Which is fine I suppose, but I want to look less like a weak stick figure and more tougher. Bigger muscles gets the females, and plus itl be healthy for my body. Problem is I don't where to start, or what excercises are most beneficial. I have some 15 and 20 pound dumbells, and an ab roller if that helps out my situation. Help ...and I'm not going for Mr. Universe here, i just want to look more fit.