Buying tear of the goddess early on your first return to base is great!! Because Volley takes a lot of mana and it allows for spamming. I wouldn't agree with starting Doran's blade. Get boots and a pot. Followed by berserkers greaves and a bf sword after that. Then work on BT and then infinity edge. After that you should follow the guide
I say again just a suggestion but it works for me when I play ashe.
I don't know if tear is such a great starting item. I do agree with you that tear is great for spam, but it's not until later levels that volley's cooldown gets low enough for you to spam it so that you can max out tear and then upgrade to muramane. If you want some mana sustain, build Spirit of the Elder Lizard. Yes, it has recently been nerfed quite badly, but you can get the important parts (mana rengen, 2 swords) early and then finish it up later. The true damage, mana regen, and extra damage against monsters are super important once your team needs to start focusing on dragon and baron.
Dorans is a pretty good starting item on Ashe because of her 600 range. The only champ who starts off with more range than her is Cait, so it essentially give you free sustain if you need it.
Don't build attack speed early. Always go for damage early since it has far more impact during laning phase than attack speed. Also, attack speed is always secondary to damage (it's why you never see any ad carries build pure attack speed).
My Ashe build is dependent on who I'm laning against but is usually:
Usually Dorans (Sometimes boots and 4 pots if I'm against a cait who I think might be aggressive)
Then if I'm ahead:
BF sword
boots
finish infinity edge/berserkers greaves depending on cash flow
phantom dancer spirit of the elder lizard botrk etc.
If I'm behind:
some of the parts for spirit of the elder lizard
boots
finish spirit of the elder lizard
infinity edge
finish phantom dancer botrk etc.
These are the runes I run on my ad carries:
Armor (Glyphs)
+ 6.3
Damage (Damage seals and marks)
+ 12.3
Lifesteal (Quints)
+6%
Guides are useful to a point, but really you just need to play and learn what works and what doesn't.