Low disksåace ?

Hi. I'm receiving this message on my 10.1: You are running low on disk space on your home partition (currently -26% free), would you like to run Konqueror to free some disk space and fix the problem? How can I increase the diskspace?. I know I can delete files/directories, but this is not what I want to do. I want to keep the content, and make the space greater. Erik