My recent GP making guide

Items needed at least 95k. More money you have the more you make.

PLEASE NOTE: You are not guaranteed profit, but I've made about 400k in about an hour doing this.

Requirements to make it easier.
-Law runes
-Air staff
-Fire runes
-Water runes

Start at the G.E. with whatever amount of money you wish to invest.

Buy crystal keys(they buy instantly at mid)

Teleport to Falador

Run to Taverly and use crystal keys on the chest.

Teleport back to G.E.

Sell items.

100% Dragon stone.
Other items, lots of runes, key halves, rune bars, coal, iron, etc

Does have risk though.