The best time to use the test is around noon or so, but anytime during the day or afternoon is fine. The only thing they usually recommend against is using first morning urine, since LH builds up in your system during the morning hours, so it might not be as accurate if you test as soon as you get up.
As for the best time to have intercourse, it's basically the day of the positive test and the following two days. Most women will ovulate within 12-48 hours after the LH surge is detected...usually the day after.
Best of luck, and Happy Valentine's Day!
The best time to test is 2 p.m., or as close as possible. Anytime between noon and 8 p.m. is fine, first morning urine is not recommended. The reason for this is that most women experience a surge in the morning, but it can take 4 hours for it to show up in your urine. Make sure to test at about the same time every day. After you get a positive you will ovulate 12-24 hours later so you should have intercourse within that time.