I've been on the pill for many years and can't really remember how long my cycle is. To check when i start ovulating again, and moreso to time ovulation so we can hopefully influence the gender of the baby, i've bought a Maybe Baby ovulation microscope. These beauties retail at $80, but i bought mine secondhand for $20. The mum who sold it to me said they were fairly easy to use, you just had to put the right amount of saliva on the slide and let it dry for 10 minutes. I had a go at it when i first brought it home, and got pebbles (as expected), which indicates i wasn't ovulating. I applied the saliva with a fingertip and that seemed to be the right amount, not too much.
According to their website, if you TTC 2-3 days before you ovulate (so when you see the transitional stage of small ferns and pebbles on the microscope) it increases your chances of conceiving a girl.
This month will be my last month on the pill, then i'll start charting ovulation for three months and hopefully will start to ovulate in that time.