Start here
http://www.d20srd.org/srd/classes/ranger.htm
Change HD to d10s - just because
Change Favored enemy so that it applies to "damage rolls" not just "weapon damage rolls". You totally should be able to add damage to a Necklace of Fireballs just as well as from a longbow.
Change Combat Style, Improved Combat Style and Combat Style Mastery to
This folds the abilities into the existing Tome Feats.At 2nd, 6th and 11th level a ranger may select one of the following tome feats as a bonus feat:
Blind Fighting, Combat School, Command, Danger Sense, Hunter, Insightful Strike, Point-Blank Shot, Sniper,Two Weapon Fighting and Zen Archery.
Change Endurance to
This folds the ability into the existing Tome FeatA ranger gains the tome feat Great Fortitude as a bonus feat at 3rd level.
Change animal companion so that
This means it won't become meaningless as levels increaseThis ability functions like the druid ability of the same name, except that the ranger’s effective druid level is three less than his ranger level.