Regardless of how you choose to train mage, you should ALWAYS be splashing when you are sleeping, not wanting to pay attention to the game, or going out, invest in the fire battlestaff thing that has fire/air runes because it does pay for itself, if you start buying airs and minds to splash fire strike, you actually save your money in the staff within a few splash sessions.
Besides splashing I would say maybe do stun alching (i know i saw someone on the /r/2007scape with an ahk script to stun alch so you could stun alch by simply pressing a few keys at a time.
OR
you could burst at ape atol on the monkeys ( more expensive but you can gain good mage xp as well as hp xp)