One night...I spent nearly 3 hours writing my ad to be short, inclusive, different..yet somewhat similar to the site I am on. But in the end I was happy at how much better it sounded than the last 4-5 ads I wrote...
I had to pull together some useful information from when I used to work for a card/invitation company and also reference to the sites. And I havent changed it since (well I did, but only a few tweaks to words here and there :-)