TTC-what time of day?

Cindy • Married 3.10.12... Baby coming 12/16!
What is the best time(s) of the day to have sex when trying to conceive? 
I'm 22, been trying for 2 1/2 years, didn't have sex Til marriage. Just started Clomid this month and hoping it works! (Have pcos, so without Clomid I don't ovulate) thanks for any help!