The favoured attributes are Agility and Endurance, although they are not strictly important since joining the Ashlander tribes is mostly to complete the main quest and not to advance in rank. They highly favour Mysticism as a skill, since prophecies and dreams are essential parts of their culture. Other favoured skills are the Spear, the magic school of Alteration, Marksman and Medium or Light armour.
The Ashlanders dislike absolutely everyone on the land, some more than others. They are slightly in disagreement with the practices of Mages, the Telvannis or the Imperial cults, whilst they strongly dislike the Fighters guild, House Hlaalu and the Imperial Legion. They also dislike the Thieves Guild since they regard them as cowardly. Above everyone else, they hate Vampires and House Dagoth with a passion, since they believe in Lord Nerevar and the Nerevarine prophecy, which you will discover as the main quest unfolds.
Each tribe has a leader, or Ash-Khan. Ulath-Pal of the Erabenimsun, Kaushad of the Zainab and Sul-Matuul are greatly respected Ash-Khans and will attack you if you visit unexpectedly. The Ahemmusa tribe has a Wise Woman as their leader, the mystic Sinnammu Mirpal. Clan ranks are: Clanfriend, Hearthfriend, Brother, Initiate, Clanholder, Guide, Champion, Gulakhan, Farseer and Ashkhan. These ranks are just for lore purposes, since you won’t be able to advance beyond Clanfriend.