I got this. I paint for a living. Purdy brush ( It's the best ) Dunn edwards paint ( No skin or chunks and always goes on smooth ) Frog tape ( for baseboard or crown molding ) Plastic ( if you don't trust yourself from not hitting the floor) 3/4 inch nap or roller ( provides the best coverage on any type of wall. Never roll dry and always go in consistent patterns or rows to keep the finishing look. Never let the paint touch the crown on your brush in order to keep it healthy looking.
Pick a color, buy sufficient paint. Make sure you have masking tape, drop cloth or some kind of sheeting for spatters, brushes rollers, some kind of plaster to fix cracks, and a good radio nearby. Enjoy yourself Picasso!
Spackling compound for nail holes, cracks and such. Sandpaper to smooth the areas you sparkle. GOOD brush (well with the extra $$) Make sure it's the correct paint for a bathroom. Kilz if you have any stains that need covered.