Man am I happy I only design for intranets where I control the browser being used. Best move I ever made. I hate trying to work with other browsers now, originally I was a w3 stickler...
Sounds like the design tips you got are good. KISS basically. Green won't be bad to work with, just find a pallette to use and work darker if the colour is light. Should be fine.
Php/mysql is a killer combo. I still prefer it over others I am learning now or have learned recently.