Try not to drink for a couple hours before bed. Then, when you wake up in the morning (or during the night to pee), force yourself to pee and use that to test. If you really don't have to go all that badly, I'd recommend collecting your pee in a cup and testing, because only a strong flow of urine will give you accurate results, and if you don't have to pee badly, you won't have a lot of urine in your 'flow'.