Deer are typically aged by how many teeth, and wear on those teeth. There are certain molars they get at certain ages, after they get their last molar then the only real way is to look at wear.
Any deer aging tool will show you this.
At a point in a bucks life the body shape plays a huge role in aging from a far, the heavier the chest and sagging belly line will help greatly in judging this in the field with a buck standing for you to judge. Hunting.net may even have this info somewhere with picks.
Here is one with drawings but I have seen some with actual picks of various aged deer in the wild.
http://www.1atexasdeerhunting.com/bodyagingdeer.htm

Deer antlers may be colored by several things but most of the time deer that bed in open swamps with alot of sunlight or fields with alot of sunlight will have bleached type racks, white or very light yellow. Bucks that bed in some deep thickets where sunshine is minimal will most always have dark racks.

a week ago I was out retrieving a duck I shot in an open marsh, I walked through some high weeds and jumped a 8 pointer with about a 19 to 20 inch spread about 50 yards from "land" and his rack was very white looking. I saw a good buck come out of another field type swamp this year while bow hunting and his was the same, very light. Where I normally bow hunt it is very thick and the bucks seen there sometimes you have to glass late in the eve just to see if they have antlers at all, at dusk it is hard to tell because their racks tend to be dark.