Mounted Archer

[Eldariel]

Biggest thing about mounted characters: It generally pays off to acquire a non-standard mount through class features - having your mounts die under you in combat sucks royally, especially if you've heavily invested in mounted archery, and if your Mount doesn't improve as your opposition gets more and more fierce, that is like to happen pretty soon.

This leaves you with a few big options:
-Pick up Leadership/Dragon Cohort [Draconomicon], try to attract a Cohort that can act as your Mount such as a Nightmare, Dragon, Griffon, Hippogryph or Pegasus.
-Pick up Wild Cohort to get a slightly weakened Druid AC, pick Mount to taste. Dire Bat is a good early option, as is Warhorse - later on you can ride anything from Dinosaurs to Dire Vultures (how's THAT for appropriate to Desert?)
-Make a build out of classes that have Mount/Animal Companion class feature. Even better, use Theurgic Mount/Holy Mount [DR325], Devoted Tracker [CAdv] or similar to stack both progressions into a single companion, then use a class like Halfling Outrider [Complete Warrior] to advance both to make a hugely buff companion/mount.


The other big issue you need to overcome is that on higher levels, archery without magical buffs has a sharply limited damage capability. Ranged Weapon Mastery [PHBII] is almost a must for a purely martial archer (with the accompanying Weapon Specialization) and you should look to other sources of extra attacks/damage if possible (Barbarian-levels with Whirling Frenzy are a good one).

Other than that, weapon enhancements are your best bet, but it's unstylish and unreliable to rely on your weapon to kill things. If possible, you'll definitely want Energy Bow though, just to make Power Shots (attack rolls are pretty easy to buff for archers, it's dealing damage that's the problem). Also, if you have access to 3.0 classes, especially Peerless Archer [Silver Marches] (other nice ones are Deepwood Sniper [Masters of the Wild] and Order of the Bow Initiate [Sword & Fist; no, not the Complete Warrior-version, that sucks]), you can get by much of this.


You may wish to take a look here:
The Archery Handbook

It's (still) unfinished, but there's a bunch of stuff there that could be of use to you.