You will start to get the hang of it after a few cycles. For the first time I did it, I started day 9 and then one I started to see a line, I would test twice a day and once the lines get dark I would use my Clear blue easy to get the smiley (around day 13) just to verify. Now I usually start day 11

I know what day of my cycle to start testing, but how many times a day should I test? Given that we're talking about just a 36 hour window of fertility, testing once every 24 hours doesn't seem like enough to me, but what do I know.