There are no hard and fast rules about what you should say because it is important that everyone comes across as an individual, but typically a Voice Greeting might go something like this:
"Hi my name is John, thank you for listening to my Voice Greeting, let me tell you a little bit more about me...
Well, I'm 47 and from Glasgow, I'm 5 feet 8 inches tall and medium build...
I work hard and enjoy the decent things in life such as restaurants, movies, friends and family, however I have been single for a few years now and I would really like to meet someone to share and enjoy life with...
My ideal partner would be a lady around the same age or maybe a little younger who is talkative and friendly...
I would like to meet someone to share nights out with and explore our interests together...
I'm friendly, honest and worth replying to... If you would like to get in touch then just leave me a little reply telling me all about you and I promise to get in touch... I look forward to hearing from you"
That should take about 50 seconds or so, and isn't too repetitive, perhaps you might find it easier if you write it down before you make the call, just make sure you don't copy our example completely... Especially if you're not a man called John from Glasgow.