First off, in Tutorial Island, make the following skills level 3:
- Prayer
- Cooking
- Fishing
- Wood Cutting
- Fire Making
- Mining
- Smithing
- And (what ever you plan to be) attack and strength, mage, or range
After that go to the mainland. Once you are at the mainland train your wood cutting to level 60 (if you are patient: ). At the same time you train your wood cutting train your fire making. Fire making levels up faster, but fire making is not necessary to train. After you can cut yews, start cutting it and then selling it. Also train your fishing. The best place is in Karamja. While training fishing, train your cooking at the same time. Once both skills are level 50, then fish and cook swordfish and sell them. Lobsters work to, but swordfish you will be able to make more money.
Also train your mining and smithing. First, finish Doric's Quest. Then mine at the Dwarven Mines, and smith in Falador. If you decide to become a mage, when your magic is level 43, you will be able to cast super heat which will speed up your leveling up of smithing since when you cast it on iron ore, its 100%. After you can make above steel items, you will be able to make a lot of money.