Preparing to take LPIC – 1 is not a small task and I think the best preparation is lots of experience with linux systems. Books in the stores are often hopelessly outdated, even if the information in the books is correct the LPI exams change as linux grows and change.
Set up a linux system and use it as your only OS during prep period
Experience is your friend. Make sure you have a system to work on and test all the commands and systems that will show up on the test. Everyday use of a Linux machine will trim you in every area of LPI whether you want it or not. It is not enough just to sysadmin a webserver somewhere, to pass this certification you have to get down and dirty with Linux everyday workstation use. Choose a distribution that use RPM or DPKG (Suse, RedHat, Debian)
Download the objectives from LPI
For each objective read the man page on the key commands and files. Then read it again
Lay your hands on me
Test every command, set up every subsystem. You need to set up a sendmail, Apache, Samba, NFS, Named, etc. write some Bash scripts for everyday use, tweak your system untill you know every dark nook and cranny. Even tho the test is a written test there will be questions that will test if you have actually grasped the key concepts not only memorized commands. Even though it is a written test it is very hands on!