I think my best peice of advice for a "noob" is this... Practice, practice, practice... Experiment. Play around with things and tinker with settings (what settings you try really isn't important)... The more you play around with things and experiment, the more you'll learn and discover! Tinker and experiment enough and you'll eventually be rendering and creating like a pro :)

Also, don't let a bad comment or bad bit of feed back get you down... just because someone doesn't like something you've done doesn't mean it's all bad... If you liked what you did then that's the most important part ;)