I’d agree with @mattbrowne – if you’re having trouble taking in (or tuning out) the city sounds around you, playing a CD of some kind could give you something more immediate to focus on. It could be nature sounds, or white noise, or even just some kind of quiet music that you enjoy.
I’m personally a huge fan of this CD of the Gayatri Mantra – it’s a great basic chant to focus on while you meditate, and it’s recorded beautifully, with a few good instrumental tracks too (plus, I know the guys who arranged and performed it!)
@AlfredaPrufrock I’ve always lived in a city, and when I visit my grandma in Middle-of-Nowhere, NJ, the silence always freaks me out for the first few days. I get used to it after a while, but I still can’t shake the feeling that there’s something missing – it’s nice to get back to the noises of the traffic and the neighbors…