Supposedly if you take it CD 5-9 you have less chance for twins, but I have seen twins conceived on every possible combo of days and I no longer think this does much of anything.
If you do decide to stretch the truth, DO NOT go in asking for Clomid. Do not even MENTION the C word. Just go in and say one of the following things:
1) you have been trying for over a year and not getting pregnant
2)you aren't ovulating and (this is very important) not getting AF regularly - like your cycles are 60-90 days in between periods
3) your LP is really short, you're only going 8-10 days after ovulation before you get AF
They may still not give it to you. IF they don't offer it freely, do not throw a fit about it, simply say, thank you and leave because they will not give it to you EVER if they get any vibe that you are a Clomid troller. There are some women out there who are cray-cray for multiples and really after the Clomid so they can abuse it and take higher doses to get twins/triplets, and obviously that is frowned upon.