Step 1: Making Money for Noobs (Newbies)
To make money with chickens go to a chicken farm (there is one in Lumbridge if you follow the northern path) and kill the chickens for there feathers. When you have around 1,000 or so go to the GE (Grand Exchange) in Varrock and sell them for the market price (usually around 6gp each).
MAKING MONEY WITH COWS
First to make money with cows, go to a cow pasture (there is one just east of Lumbridge castle and one behind the Lumbridge mill. The Lumbridge mill one is better because there is a bank deposit box there). When you get there take the cowhides that they drop when you kill them and when you have 500 go to the GE and sell them for the market price (usually around 114gp).
MAKING MONEY WITH BONES
To make money with bones go to a place that has creatures that you can kill quickly (For example: just east of Lumbridge there are low level goblins). Then kill as many as you can and pick up the bones that you are given when they die. Bank them and when you have collected 500 of them go and sell them on the GE for the market price (bones:76gp--monkey bones:193gp--burnt bones:192gp--big bones:339gp). (To get big bones you need to kill dragons)
HOW TO GET MONKEY BONES
To get monkey bones you will have to go to Port Sarim with about 200gp and talk to a captain or customs officer to get a ride (that is what the money is for). Take a ship to Karamja and go into the jungle. When in the jungle you will see monkeys kill them and they will give you monkey bones. There is no bank on Karamja unless you are a member so you have to go back and forth between Port Sarim and Karamja.
MAKING MONEY WITH MINING
To make money by mining first mine copper ore (you can mine copper ore south of Lumbridge castle) until your mining level is 15. Once it is level 15 then go just and south-east of Varrock and there is a mine. You will find 3 iron rocks (you can prospect them to find out what they are), mine from those rocks and bank them north of the mine until you have 500 and sell them at the GE (iron ore sell from between 99-101gp).