I read a lot of 'HOW MAKE MONEY??' threads and people always choose slow and boring methods while they shouldn't.
The easiest money making method ever is herb farming.
There are five patches:
Port Phasmatys
Falador
Catherbye
Ardougne
and Trollheim.
1) You plant your seeds in all four or five patches. Use supercompost
2) Do something else for two hours, like training or another moneymaking method.
3) Go back to your patches, harvest them and plant new seeds.
This takes around three to four minutes and usually yields 150-200k. That's equivalent to 2-3 million gp/hour and it's also a nice break from whatever you were doing. It used to be a lot more but they've been crashing lately.
Stuff that helps tons;
Supercompost:
ALWAYS use this. I can't stress it enough. It boosts yield and makes your herbs less likely to die. You can also use a lunar spell that does this.
Magic secateurs:
Boost farming yield by 10%. The quest that rewards this also gives a hefty chunck of farming experience and it's also very short. This is a must-have.
Ectophial:
For quickly accessing Port Phasmatys patch.
Scroll of life:
Gives you a chance to get seeds back when harvesting. Must-have.
Explorer ring:
For quickly accessing Falador patch.
Trollheim teleport+My arms quest completed (<- very funny quest, would recommend you to do it):
Unlocks trollheim patch.
Ardougne cloak 3/4:
Quick access to ardougne patch. Use combat bracelets-> ranging guild or skills necklace-> fishing guild otherwise.
Falador shield 2/3/4:
Bonus xp when harvesting Falador patch.
Juju farming potion:
Reward from Herblore habitat. Boosts herb yield by 33%
Remote farm spell:
Lunar spell that allows you to check the health of your patches. Unlocked after 18 hours of Livid farm(<- extremely boring)
Trollheim Teleport:
Teleports you extremely close to Trollheim patch. Unlocked after 40 hours of Livid farm.
Use this calculator to decide which herbs to farm:
http://runescape.wikia.com/wiki/Calculators/Farming_herbs
I'm still going to add other methods and add pictures.
The easiest money making method ever is herb farming.
There are five patches:
Port Phasmatys
Falador
Catherbye
Ardougne
and Trollheim.
1) You plant your seeds in all four or five patches. Use supercompost
2) Do something else for two hours, like training or another moneymaking method.
3) Go back to your patches, harvest them and plant new seeds.
This takes around three to four minutes and usually yields 150-200k. That's equivalent to 2-3 million gp/hour and it's also a nice break from whatever you were doing. It used to be a lot more but they've been crashing lately.
Stuff that helps tons;
Supercompost:
ALWAYS use this. I can't stress it enough. It boosts yield and makes your herbs less likely to die. You can also use a lunar spell that does this.
Magic secateurs:
Boost farming yield by 10%. The quest that rewards this also gives a hefty chunck of farming experience and it's also very short. This is a must-have.
Ectophial:
For quickly accessing Port Phasmatys patch.
Scroll of life:
Gives you a chance to get seeds back when harvesting. Must-have.
Explorer ring:
For quickly accessing Falador patch.
Trollheim teleport+My arms quest completed (<- very funny quest, would recommend you to do it):
Unlocks trollheim patch.
Ardougne cloak 3/4:
Quick access to ardougne patch. Use combat bracelets-> ranging guild or skills necklace-> fishing guild otherwise.
Falador shield 2/3/4:
Bonus xp when harvesting Falador patch.
Juju farming potion:
Reward from Herblore habitat. Boosts herb yield by 33%
Remote farm spell:
Lunar spell that allows you to check the health of your patches. Unlocked after 18 hours of Livid farm(<- extremely boring)
Trollheim Teleport:
Teleports you extremely close to Trollheim patch. Unlocked after 40 hours of Livid farm.
Use this calculator to decide which herbs to farm:
http://runescape.wikia.com/wiki/Calculators/Farming_herbs
I'm still going to add other methods and add pictures.
you could make tons of cash this way 
