I'm no Ashe expert, but I do enjoy playing her; I'll try to answer what I can:
Does Crit Damage Runes work on her?
I mean, sure, they work. I don't think they're optimal, however; I just stick to the standard ADC runes
I don't feel like I do nearly as much damage as others. I see other ADCs critting for 1k every shot or w/e, I just don't know how to keep up.
So Ashe has a unique mechanic with her passive, where she will guarantee 'crit' anyone who is affected by her passive (ie. the slow; not any slow, just the slow from her passive). This 'crit' does damage based on her crit chance stat (plus some base bonus damage), so it's not a regular 2x damage crit that most other champions have. What this means in game is that Ashe's damage is more consistent, where other champions might hit random crits for massive damage, then not crit at all dealing less damage. Over time it roughly equals out; you won't be seeing massive numbers like other ADCs, but your DPS should be pretty much the same over the long term.
Also any general tips for when to use Q? Other than just chasing?
Her Q is her steroid, so use it for extended trades and fights, or taking objectives; if you're doing a short trade it's better to just AA + W + AA or just W + AA and back off, imo. Doing so will guarantee a crit (you can auto before you use your W since your W resets your AA animation, but you want to be able to auto attack after they're slow because you get the guaranteed crit).
And is Ashe "good"? lol Well that's a hard question. Is she viable and when is good to pick her?
Any champion is 'good' if you're good at them; for the vast majority of players, champion selection won't make or break a game, it depends on how you play them and your game fundamentals more than anything. Put differently, buying the latest champion won't suddenly make you a better player, unless of course that champion really meshes with how you play the game to begin with, or if you can learn them very quickly (which, again, means you have to practice and learn how to play the champion, not just pick them up and expect to do well)
That being said, Ashe is a great champion; she is (or was, before Kalista) known as the queen of kiting because of her slows on her attacks, which means she is extremely effective at kiting, especially vs kitable champions/teams. Like most ADCs without a dash of some sort, she's vulnerable to hard engage, though she does have more self-peel than many ADCs with her ultimate and slows. Ashe is primarily picked for her utility (slows, vision, and her ultimate), and her ability to provide really consistent and predictable damage. She's a great champion to learn the ADC role as well, just because her kit is pretty easy to pick up. Ashe is pretty well rounded, so you don't have to worry as much about match-ups I think, just be mindful of your opponent and modify your play accordingly.
