This is a great way to see when
you ovulated so if
you do it for a couple cycles,
you can start to see a pattern (more than likely). Women who do this get very good with this method and are able to tell when they ovulated very accurately.
You could look for signs of ovulation, such as checking for fertile cervical mucus, ovulation cramping, etc. A lot of women do not experience overt signs of ovulation so this isn't best method but it can be helpful.