Check every time you go to the toilet. Wipe front to back before you pee, then look at what's on the paper and feel it between your fingers. Log the wettest thing you saw that day.

• Dry or sticky: low estrogen, low fertility
• Creamy: estrogen is rising
• Watery or egg-white: peak fertility, stretchy between your fingers

Wash your hands, squat or put one foot up, and reach in with your middle finger. Check at the same time of day so you compare like with like.

• Low, firm, closed: feels like the tip of your nose. Not fertile.
• Soft, high, open, wet (SHOW): feels like your lips and is harder to reach. Peak fertility.

Start testing a few days before you expect to ovulate. Test at the same time every day, ideally in the afternoon, and don't drink a lot in the 2 hours before.

It's only positive when the test line is as dark as the control line, or darker. A faint line means no surge yet.

Take it the moment you wake up, before you sit up, talk or check your phone. Use a thermometer with two decimals, orally, at roughly the same time each morning.

Draw your coverline just above your highest low temps. When your temperature goes above it and stays there for 3 days, ovulation is confirmed. It only tells you after the fact, which is why you pair it with mucus and LH.

Apps predict from your average cycle length. They measure nothing in your body. Track these four signs by hand for at least one cycle and you'll start to feel the shifts before you measure them.