I am sure that I have stated that you don't need any trained skills to be a millionaire and if you have read the first part of this guide you know that you do not. However, I decided to add this chapter just to help anyone out that wanted to train some skills to get rich. Here are the best skills to train and you can see the following chapters on the best way to train these skills.

Mining
A player who can go into the mining guild earns money fast. Sell Iron ores for 50 to 100 each, Coal for 150 each, Silver for 200 each, Gold for 150 to 300 each, Mithril ores for 250 to 300 each, Adamantine ores for 900 to 1k each and Runite ores for at least 10k each.

Smithing
When you've got a decent amount of money, you can buy ores/bars. Smith them to get your level up. It takes a long time, but you earn a lot after you can smith rune items.

Fishing/Cooking
Train fishing up to level 40 so that you can fish lobsters. Before that, fishing doesn't really earn much money for you. Fish lobsters and sell them. Cooked lobsters sell for more and are easier to sell so I'll recommend cooking them. You need a cooking level of 40 to cook lobsters. Sell cooked lobsters for 150 to 200 each.

Woodcutting
A skill that earns a lot of money, but you need a lot of patience. Keep training your woodcutting level by cutting trees until you can cut oaks. Then, keep cutting oaks. Even though willow trees give more exp, I've noticed that cutting oaks give better overall exp. Cutting oaks give more exp per hour because you miss less often, as compared to cutting willows. Once you've got woodcutting level 60, go cut yews. I would strongly recommend you use a rune axe before cutting yews, because it takes a long time. Sell yew logs for 250 to 350 each.

Crafting
Not recommended for non-members but it is still a way to earn money. Craft gold bars into necklaces/amulets/rings and sell them to the general stores. The only good way of earning money from crafting is by making diamond amulets (requires crafting level 70), enchanting them into amulets of power (requires magic level 57) and selling them for about 10k each. A good way of leveling up crafting is by making holy symbols, as they give 50 exp each.