When ttc your best bet is to have sex every other day (gives your sperma chance to build back up, rather than everyday)
start around day 7 or after her period is finished (although rare some women do ovulate right around their period)
by having sex every other day, there should be sperm hanging round even if you don't actually have sex on ovulation day.
But it does seem that the harder you try the less likely it will be.
So best of all have good sex and if one of you isn't interested that day, so be it, don't push it, just enjoy it.
Hope you get the answer you are hoping for