[dfw-guy]

Texture, smell, color and my fav method, smoke before you buy :)
In my experience...
Good weed generally has a strong oder, of which depends on the strain.
Good weed is sticky and seems moist, but will still burn readily and not crackle or pop. The stickiness is all of the lovely resin.
Color really depends on the strain, but I would be cautious of any weed that is both dry and has brown undertones.