Im pretty new to Blender and modelling in general but thought I would post one of my renders. C+C welcome.
Heres another render
Very nice… When I started out I couldn’t make anything, I still barely can 
But I keep trying, keep up the good work.
Welcome to Blender! Very nicely done for a first modeling project. Do you have a photo of the wireframe? Now, to the stressful part, critique! There are a couple things that would make this so much better. First one is a major one, Lighting. Right now the lighting is not bad, but it could be more. What you want to do for the lighting is the 3-point system. Here is a video tutorial/article on that system: http://www.blenderguru.com/videos/mastering-lighting/
Second one is for you to consider adding the power cord with the little switch that usually comes with the lava lamps. It will add so much to the realism of the model. Other than that, pretty good. Definitely would like to see the wireframe of this. Keep up the great work!