Lots of people share their methods, I like this one:
“I store all the pills in one bottle, and a week’s supply in the other bottle. I take one pill from the week bottle every day. On Sunday, when I have taken the last pill from the week bottle, I put 7 more from the other bottle in there.
This way, if I wonder whether I took it, I simply think about what day it is and then see if I had taken my pill that day based on how many are left. It works really well.”