I wudnt recommend Catalyst, too money intensive early game and wastes a slot later. But that's also not my item build, I go intensive DPS, which I've found is much more effective. However, you also need to play smart and have a good tank, which isn't something you find in every game.
Wow, way to be wrong....
Catalyst doesn't waste a spot later. Its in the receipe of Banshee Veil. Every Ashe should have a Banshee Veil late game because you'll be the #1 target in team fight. Also, you should get it earlier (like mid-game) if theires alot of caster on the other team. Catalyst is cheap and it's the best first item to get on Ashe.
Ennyn guide is decent, but going catalyst the protector is better.
Personally I think this guide is the best noob-friendly Ashe guide: [GUIDE]Scoits's Guide to Ashe
There's alot of tips how to play Ashe, harrasing, last hitting and more.
Comment below rating threshold, click here to show it.
I'm working on marks and quints=armor pen, and everything else crit damage.
Pretty much maximizes your damage potential in my opinion.
Works for all carries I can think of. Gives your crits a significant boost in damage and penetrates more armor. The more armor you penetrate, the more damage you'll be doing BY FAR.
Of course, you can get last whisper and get pretty much the same effect, but I like to get malady after IE and PD for the speed and lifesteal, rather than the speed and armor penetration. (Having armor pen runes and last whisper is a bit overkill, except for tanks.)