In party development, you need to get everyone up to expert in their core skills as quickly as you can. If you're running a party containing two archers, I would certainly develop all their magic skills, but how you do it would depend on how many other spellcasters are in the party. If the archers are the only two, I would get one up to Master in Water asap, so you have access to Town Portal, and the other up to Master in Air so that you can use Fly as effectively as you can. Fire is very tempting, I know, but I think those two spells take precedence. Also, when they are fully promoted, if you're on the Light Path, I recommend that everyone who can learns Light, and gets the Paralyze spell. It's the single most important combat spell for a Light Path party.

Don't boost your bow skill at the expense of your melee skills. Unless you're fighting against ground-bound opposition with a river between you, sooner or later, they're going to reach you, and bow skill is then useless You need to be good at both ranged and melee fighting.

You also need to find an item "of Thievery" or "of Disarming" if you're relying on one of your Archers to open treasure chests etc. for you. They're not good enough without that, and it's a wearying job to have to keep repairing your party because things keep blowing up in your face.

A decent bow "of the Dragon" is a top level weapon, and you will need to kill a top level monster to get it – a dragon would do nicely

Good luck!