That you O an average of 24-36 hours after the FIRST positive, not the darkest;
And that it is not positive until the test line is as dark or darker than control (a faint line is not positive)
And that you can't tell when exactly you Oed based on how fast the tests go back to negative...you can have a positive test still and already have Oed, or your test can go positive before you've Oed. There's no correlation, the test just measures the surge of hormones and not the actual egg being released.
Those are the big q's I get a lot.