So you don't think training style has much to do with it? ie: High reps, low weight or vice versa, strip sets/drop sets, higher frequency...?
I do agree with Luv that alot of it has to do with diet (unfortunately), but in terms of building the muscle mass and increasing strength (I do think that stronger muscles look harder because they are denser)...I would go with a lower rep, higher weight kind of approach. Strip sets, drop sets, and things like that will help to burn calories and get you leaner, but not so much build mass.
I guess that what you gotta do is over time, grow the muscle with a heavy, low rep kind of program, while eating clean enough not to get fat, and then maybe go with a higher rep approach with lots of drop sets, etc. to shed the excess fat and get the real hard look going. Sounds like contest prep to me hahaha...