Are you planning on botting for money or you would just like basic tips if playing legit?
Either way: botting, you can merch, snape grass, fish, wood cut, simple stuff like that
Legitly, you can go to barrows, only need for 43 prayer and like 41 mage for that nothing too specially , watch some videos on low levels doing barrows. anyways, you can kill blue dragons/green dragons for money, fairly simple, kill chaos druids/flesh crawlers and collect their unidentified herbs, sell them for some monies or skill on your own, makes slow money but it's still progress.
Good luck pal