Jim has some very good points, but I have a suggestion that may speed the process. After washing the walls with TSP, as he suggested, try using Zinsser Cover-Stain, available at most home centers and paint stores. This product is oil based, has excellent adhesion, and will stick to glossy surfaces with no pre-sanding required. I painted exterior glass with it and is still sound as ever. The directions too claim no prep necessary on glossy surfaces, they show it being applied to ceramic tile !! As for Jim's suggestion on paint quality....heed his words. You will have a much better job w/ easier application by getting $18 -$20/gallon paint vs. $10 -$12. Get the best they make at the place you go to and apply both products with a 1/4 inch short nap roller, since it is a smooth surface. Have Fun !!!