I test daily before I go to the gym. Might not be the best way, but I can't help it.. kinda like getting on that darn scale. I use ReliOn Ketone test strips, and you can get them in the diabetic section of the walmart pharmacy. All you do is pee on them, and then compare the strip color to the color panel on the side of the bottle. It ranges from negative to large. I like to see where i'm at before going into the gym. If i'm in large, I know i'm hopefully going to burn some good fat on the track.
Good luck! Calorie counting has always freaked me out, and I don't have the patience. Not saying it's a bad thing, it's just not for everyone. You might have some fluctuations happen as you transition, but I bet you'll do just fine.