Cut logs.  You will increase your ability, plus you can sell them at the Grand Exchage to make money.

Mine.  Go South of the Grand Exchange to the small mining area.  There is one rock that contains clay.  Mine this clay and sell it at the Grand Exhange for a good profit.

Once you get off training island, make your way towards the Grand Exchange.  On the way, stop off where the cows are located.  Kill cows, and collect their bones, meat and hides.  You can sell this all at the grand exchange.  Between the meat, bones and hide, you can easily make over 200 gp for each cow you kill!

Once your mining level and smithing level are both to level 30, start to smith coal and iron.  Once you have 1k of each, turn them all into bars.  Next, go to an avil and turn all of the bars into steel or iron weapons.  Sell these for big profits!

Get some trout, then head out to the wilderness.  Find a fenced area and pick up all the planks and bones you can find.  Then head to the Grand Exchange and sell for a good profit!

Check back in, we will continue exploring how to make money on Runescape!