Lol there are many methods that can make 300k/h without botting, for example, doing something a bot does, only legit? made me lol
On topic: it would help if you posted your stats, if you something that has no reqs try running/spinning flax, thats about 150k/h and if you play enough could eaily get you 5m in a week.
Unless you have high ranged and high combat, I would advise against green dragons because most lower-combat people (80-105) who kill them only earn around 300-350 k an hour.
An easier alternative would be to go with chaos druids north of ardougne if you are anywhere from level 30-105 looking for REALLY fast cash. You can earn 300-350 k an hour (400 if you go to a PvP world) just by getting the herbs. There is a thieving requirement however, which I forgot.