Comments, Input, and Suggestion on my 20gallon setup please!

[inspire]

I just set up my tank about 2 weeks ago and added my live rock. I have a 2" dsb. I know i should increase that to 4". I have 96W of pc lighting.
I was wondering, my live rock sits on top of my sand bed, should i put my rock directly on top of the glass aquarium floor and then put sand around it? or is my current setup of having my live rock on top of my sand good enough.
Thanks!
I need input and suggestions, please tell me if i am doing sometihng wrong. I am a newbie at this! so please bare with me!
here are a couple pics....