Where can I learn more about what quests my clan can do to earn the rep points so we can buy some clan skills? Are the level 5 clan skills even worth it? What is the best way to earn these points?
In my opinion, clan skills are not worth the Clan Reputation Points. They do not affect enough people in the clan to be worth it. Don't spend your Rep Points on Clan Skills, invest them in getting the clan levels and the royal gaurds.
As far as I know, the only clan 5 quest to get Reputation Points is the one with Eric Rodemai in Aden, where you have to kill high level raidbosses. If your clan don't have allies, that may be a bit tricky.
My best bet is to get Academy members and work them up to lvl 40. You get 400 rep points if you let them join academy no later than lvl 16. After that, the points will decrease with 10p for each level.
Academy is one of the best ways to get rep points. There are quite a few lower level players around either re-rolls or alts, that you can offer to sponser and let into your academy. Takes a while, but you can also do an academy night for all you present clan and have everyone do an alt for the clan.
i think certain skill work on all or most clan members
clan health and mdef
The skills that work on just about everyone are:
Clan Vitality
Clan Lifeblood
Clan Magic Protection
Clan Imperium
Clan Luck
These are all the clan skills available when the clan is level 5, except for Clan Luck which is a level 7 clan skill.
Almost every other clan skills only affect like, 3 people; more if there are heroes in the clan.