How to get the new ios 7 on my iphone 4s?

I want to update my ios to the new one but i have no space left on my phone, what do i do?

Settings>General>Software Update

Offload some of your pics/music/etc to your computer and then delete it off your phone.

At least, that's what I would recommend for and Android of Windows phone - I don't know if iPhone allows you to do that but it would be pretty stupid if they didn't.

You need to delete some stuff from your phone to make some space.

Backup your photos, movies and music to computer and delete from iphone then try update

The problem is applying the update over the air (OTA) which requires more space on your device, space for the download and then extracting the file.

You are better to to update via iTunes using the USB cable, not only will it be quicker its a slightly safer method in case something goes wrong as you'll have backup you can restore from. Check the link in the source for the downloads of iOS 7.