Archery is for ranged fighting. This is good, because you can do damage to your opponent and stay safe unlike melee fighters. The difficulty is making sure you are far away enough to reload safely, but not so far away that your shooting range is limited. 

As an archer you will need a ridiculous amount of arrows or bolts. If you train in fletching you will have a 99% chance of success to make these with only 30% skill level. You will need to gather wood from the forest and kill birdies or harpies for feathers. Also, centaurs, ratmen mages, and juka lords are usually good sources of free arrows after you kindly explain you would like them to die and give you all their belongings. Alternatively, you could buy arrows and save time. I personally recommend doing just that!  

SKILL TRAINING

Archery is another one of those difficulty based skills. The key to successful weapon training is to fight a creature of your own level, and close enough to your own level, so that you will gain skill off it. Experimentation is essential so try shooting different creatures to see which animals you gain off best. Remember the ones that were too hard for you, because they will be good later: 

Once you reach 70 after fighting basic creatures there is a speedy way to train up to 100 and as high as 120 if you have the scrolls to do so. This method involves you purchasing or making a Grand Master Tinker crafted Golem. You must also be in a guild for this trick to work. If you’re not in a guild, you can create your own one man guild for a mere cost of 25k gold pieces. Just buy a guild deed from any banker. Once you are in a guild and you have your Golem ready you will also need to find a 100% poison damage weapon that would be applicable for the skill you are about to train. In case of archery, you will need a 100% poison bow. The type of bow is not important as long as it is 100% poison, because golems are practically immune to poison damage; and because of this while training you will only damage it 1 health point per hit.  

Also, you can completely prevent Golem from hurting you. This is where being a guild comes into play. Stand next to your Golem inside a guarded zone such as Luna Bank or the outskirts of Luna City. Now, type in the command “All Kill” and click on yourself. Immediately after, you will take initial damage from Golem hitting you, now say “All Stop”. Right after that say “All Guard Me” and if you do this successfully and quick enough after initial damage, Golem will stop attacking and switch to guard mode. While you continue hitting with your weapon Golem will just stand still and not attack you. You will gain quite nicely for a while but eventually poor Golem will be hurt badly. If you are training near Luna bank you can conveniently stable him in the Luna stables next to the bank. It will take a few minutes for Golem to recover his health and then you can claim it from stables and repeat this whole process.

Good luck on your weapon skill training!