Honestly I say just go for it, it's basically 3D coloring books. Picking an attractive color scheme is very important, then it's just brush control and learning the general techniques.
A couple round brushes size #0, #1, #2 and a set of paints is really all you need. Youtube is a great place to learn more.
This paint set is currently a pretty good deal with everything you need to get started, including some models and a helpful guide.