And of course you also have the option of using Enamel paints on your miniatures. These are oil-based and will often allow you to give a "well seasoned" look to the adventurers, rather than the "just bought my stuff in Adventurers-R-Us" appearance that some paints do. The paints that are made for Humbrol and Airfix models are extremely good.
It's also recommended that you avoid using colours directly from paint-pot to miniature. (You can break this "rule" if you want, of course). You can have fun mixing small amounts of colour on a piece of hardboard or some other suitable non-porous surface. If you don't go the "official paints" route, you'll need one each of red, yellow, white, black, and dark blue, from which you can mix most colours you might need. As the previous contributor suggested, a ready-made "flesh" colour is very useful, and it's worthwhile looking at special bronze, silver, gold and other matallic paints as standbys.
Keep your brushes clean, and your work surface tidy. Take frequent breaks to help your eyes. Work in a well-ventilated room. Probably better not to try to paint a miniture from start to finish at one sitting. Most of all, have fun!