In addition to measuring body temperature, there are other ways to find out how your cycle works. For example, you can check your cervix yourself. By placing one or two fingers in your vagina, you can feel at your uterus where in the cycle you are.
What you should feel:
Not everyone is the same, though:
Once you have given birth, your uterus may always be open
If you have scar tissue on the uterus, it may feel different;
You may not feel anything.
If you keep to a schedule and take notes on what you feel each day, and do this for a few months, you'll get a good insight into your cycle. Note each day:
Do this for a few months and you'll get a feel for when you're fertile and more likely to become pregnant.
From Cassandra-Harmon In Q&A