How To Track Ovulation Apart From Opks? Please Suggest..

Hi all,
I have been trying for my second baby for past few months and haven't succeed yet..I tried with opk for a couple of months and it didn't work out.
I haven't tried bbt tracking.. Can anyone suggest good thermometer for this? How does it work?
Do you suggest any other methods to track ovulation?
Have you used progesterone test strips? I just saw online that it's used to confirm ovulation. Anyone used it before?

Thank you..