Tips on how to conceive

Hi girls me and my partner have been having unprotected sex no for the past 9 months and nothing has happened, at the end of July we decided to start trying for a baby....and started taking him/her pregnancy vitamins and also using conceive plus lube during sex, I’ve also been putting my legs up high after having sex. Anything else you girls could recommend? I’ve got a under active thyroid and have a 2 year old to a previous partner. Thank you in advance x