Q: how do you get hard muscles, rather than defined muscles?

A: As I said in http://www.mikesfitness.com/content/strong-or-hard-muscles you have no control over the hardness of the actual muscle. By losing the fat the covers the muscles (in other words, by decreasing your body fat levels), you can increase the apparent hardness of the muscle. Aside from that however, the only way you can get harder muscles is by tensing/flexing them.

The definition in muscle also comes from low body fat levels. So in the end, the only thing you can do to achive both hardness and definition in the muscles is lose body fat. There's nothing else you can do to increase hardness rather than definition of your muscles.