When you’re most fertile, your cervix tends to be high (not low), softer, and more open. Ovulation nearly always occurs between 12 and 14 days before your period starts. This can be fairly easy to work out if you have a regular cycle, but a bit more tricky if it’s irregular.
Changes in your cervical mucous can also signal when you are fertile. You are most fertile when your mucous becomes wet, clear, slippery and sometimes stretchy. It can be a bit like raw egg white. This fertile mucous helps the sperm travel on its way up through your uterus. It nourishes and protects the sperm as it travels towards your fallopian tubes to meet your egg.
You may find babyworld’s ovulation calculator helpful http://babyworld.co.uk/2012/03/ovulation-calculator/
Hope this helps. Good luck!