i would start also knowing the taste of your oral tabs, you will need it in the future. Some guys a buy gear off of consistent and sometines I have to go to different sources around my way because my guy is out, So before I give them the money I sample one by tasting it this helps me out.
They should pass the crush test with your thumb, like someone said above, should be approximately the thickness of a nickel, and should have 5 sides, a recessed edge, and a line across one side.