Archer Guide

If you want to be a good archer, you should be going for a STR, DEX, MAG archery build. Shalore probably since it's the strongest race in the game, though you could go for Cornac if you really want an extra inscription slot (3 is really all you need, movement infusion, phys/men wild, heroic infusion).

Why MAG as well? Simply because you then get access to Arcane Might, which increases your archery power by ridiculous amounts. Your second talent is up to you. Vital Shot, Cauterize, Spine of the World, Draconic Body, Draconic Will, Unbreakable Will and Eye of the Tiger are all fine to have.

The 4 trees you get are Wild Gift/Harmony from the sandworm queen (all you want is the healing nexus to negate the 500-20K heals enemies will occasionally do, especially since practically everything has vitality), Celestial/Light from Ano escort (only really for the chance to spell crit on Bathe in Light), Sniper because it gives you like 3 additional talents that mark the enemy, and finally, munitions to penetrate that pesky 100%+ phys res.

Note that harmony does not make you anti-magic. In higher difficulties, it's vital to have an ano escort, to such a point that there's no reason to even continue a run if you don't get one.

(Note: NEVER EVER PICK CON. Con is a useless dump stat. You'll get more health from an item or two than you'll ever get by dumping 20-50 points in con. If you need stuff in con for talents or)

A general talent guideline:
Technique/Archery Training: 1/1/0/0 (this tree is a massive stamina consumer, and thus generally is ignored. It doesn't do as much damage as consuming marks does, thus it is ignored. Pining can be given more points if you really want to pin them for longer (if you don't have enough health, armor, armor hardiness and/or phys res for melee users) but beyond that it isn't necessary since its primarily used as a talent that marks).
Technique/Archery Prowess: 5/1/4/2 (this is the most important tree and gets the most points as a result. It could even be thought to give it 5/2/4/4, but that is depending on how many points are left for you)
Technique/Combat Techniques: 1/0/0/0 (this tree is a trap, with its first talent being the only useful one to have as a one pointer, though maybe rarely with a few more)
Technique/Combat Veteran: 0/0/0/0 (this tree is a trap, only use the first talent temporarily and make sure to remove any points you put into it before you level up)
Technique/Marksman: 5/2/1/0 (this is an important tree since it gives a powerful marking tool, stamina regen and damage buff. The last talent isn't very useful because it takes up so much stamina for such a small buff)
Technique/Reflexes: 2/2/2/2 (this is the primary defensive tree, but has quite a bit of diminishing returns in it. thus only 2 points in each is necessary)
Technique/Sniper: 2/2/1/2 (if you have more points, it can go to 4/5/1/2, but depending on how you play depends on how often you need concealment active, which determines how many points you want in Shadow Shot. Aim is so low because it actually doesn't give that much per level, and we really don't want more projectile speed, more on that below)
Technique/Munitions: 2/2/2/2 or 3/3/3/3 (dependant on the amount of points you have really)
Technique/Agility: (It doesn't mark anything, so it isn't bothered with)
Cunning/Trapping (don't bother)

Generics: (extra points can go into your class tree)
Technique/Combat Training: 5/1/5/0/0/0: (Thick skin only if you have extra points. Don't worry if you don't have any, you should have plenty of resistance items anyways. You need one point in heavy armor training to wear heavy hats, boots, gloves etc that doesn't impact your mobility tree. Light Armor is where we want to be going because we have Trained Reactions in mobility. I usually go for 3 but you can go to 5. Accuracy is usually a temp slot, make sure to remember to remove the points in accuracy before each level up so that they aren't permanent. Many equipment later game gives enough accuracy.)
Technique/Mobility: 1/1/1/2 (this is a fluctuating tree depending on what you need. At most, it can go 5/3/3/4, but you are unlikely going to need all that, or have the points for it)
Cunning/Survival: 0/0/0/0: (one point in the first talent only as a temporary floater that is vital in the early game but invalidated later on. Remove it when its no longer necessary. If you have extra points and lots of charms etc, you may enjoy device mastery. Track is not necessary as clairvoyance wands exist.)
Wild-Gift/Harmony: 1/1/1/1 (we only want this for its ridiculously powerful healing nexus, the rest are bonus)
Celestial/Light: 1/5/1/3 (Bathe in Light is ridiculously OP. Spell crit on that think is ... wow. You may decide to have it be 1/5/0/0 depending on how your gear went for stat clearances.)
Technique/Conditioning: (don't bother with it, it may seem nice but you need the category points for far more important things that help you win in madness difficulty)

How do you play archer? Well, all you do is focus on marking the opponent. Everything you do should be focused around that. Just chaining marks. Generally what you start out with

Tip: When you are in a long corridor you can frequently get the stronger enemy to get stuck behind a weaker one. At this point remove all damage retaliation equipment and talents as to not accidentally kill the weaker one in front. All you do now is activate Flare on the enemy in the back and use Headshot on it. Again and again till it dies.

Gear? You focus on what you would for any other class: Phys res, stun imm, speed boosts, armor, armor hardiness, phys damage boosts, phys damage pen, crit reduction, crit damage reduction, crit chance, crit damage boost, max health, debuff clearing gear, magic dispersal gloves, stone wall gear, clairvoyance wand and finally a Burrow mindstar.

However, DO NOT PICK STUFF THAT INCREASES PROJECTILE SPEED! This is actually quite important, as a powerful archer tool is to be able to utilize two talents for one mark. If the enemy is a distance away and marked, you first activate Called Shots on the enemy. This procs its "if enemy is marked" ability, firing three projectiles. However, it is too far away for it to hit in that turn, so the mark is still on the enemy and the Called Shots is in the air. At this point you activate Headshot, hitting the opponent with your Headshot AND Called Shots for just one mark!

If you aren't doing madness, Skelly Archer is fun to use however your inscriptions and talents are going to be subpar. You don't get to use infusions (which are vastly superior to runes) and you don't get access to Wild Gift/Harmony and instead get Corruption/Vile Life.