Rules that I follow:
1. I typically only get hastened (3rd item) if they have a certain god that requires a lot of chase down. I.e., Chang'e, Ama, etc. If you need hastened to get a kill on any god without insane movement speed, it's because you need to get better at utilizing Arachne's 3.
2. Get qins only if they have a warrior or guardian solo laner building tank and/or hybrid. Don't bother building it mage or assassin solo.
3. Talaria, or boots at all, are not necessary -- especially if you're going hastened. I play extremely aggressive, both in terms of early kills (which she's the best in the game besides maybe Thanatos) and invading farm. Because of this, the movement speed is helpful with invades, and the mp5 helps having the ability to spam your 1, which leads to A) more gank potential and B) more sustainability in the jungle from healing off your 1 whilst having the mp5 to keep that up.