It's a good question to ask. The thing is, you also have to know where your limits are, and how to expand them. Anatomy, muscle rigs, and attention to detail are all key things - I for one enjoy some of your works, but I often feel they don't lend themselves well to realism, and thus are a bit detracting in that regard.

ok I will take on count on that ;)

Following what Kaiser said. Its good to study Anatomy and have an eye for detail.
You're models seem rushed more then half the time, I believe you have amazing potential.

As for your renders. I believe the lighting is boring and off-putting. I would also like to see reflections, so the scene doesn't seem so diffuse and boring.
I would be open to show you a few tips on rendering if ya like.

You are my friend dude, I do hope this doesn't hurt your feelings in anyway shape or form. *Hugs!*

ok, more to consider x3