There are a few things you should do before you begin.
If you have not yet read the installation chapter (chapter 2) of Matt Welsh's book Linux Installation and Getting Started, you should probably do so now. It covers important issues like partitioning, file systems, swap space and LILO.
If Linux will coexist on your machine with OS/2, you will need to create your partitions with the OS/2 partitioning software. During the installation, do not create new partitions, but set the partition types properly for the Linux partitions.
If you will be connected to a network, be sure you know your IP address, network address, net mask, broadcast address, gateway IP address, and name server IP addresses.
You will need two formatted 3.5 inch high density (1.44Mb) floppy disks for the installation boot disk and root disk. You may want a third disk to create a boot disk for your final system.
Read all of the installation instructions before starting the install! This way you can be sure you will not run in to any surprises and you will be prepared for all the decisions you need to make.