well this isnt very in depth... but basically buy as many essences as you can. Then buy an air tiara and make air runes until 30 runecrafting. Then buy an earth tiara and play fist of guthix. Buy earth runecrafting gloves and keep using these until 99 runecrafting (it will take forever).
If you have tons of cash you can make body tiaras starting at level 1 for very fast xp... bring 14 empty tiaras and 14 talismans and use them on the body alter.