I play my mage as strictly a healer.
I suggest first 5 points into life and the rest into intelligence. I use items with heal mastery. Try to find focused heal charms as your average heals will be higher.
If you elect to go the mage caster route, spend time in the arena building proficiencies. Intelligence gear is the tool here.
Good luck on your mage.
Also, check this out:
http://forums.d2jsp.org/topic.php?t=34945092&f=272This post was edited by BigDuke6 on Jun 17 2010 11:08pm