How should I go about installing MacOS X (any version)?

The installation process, is pretty simple, however there are a number of things you need to know first before installing X on your Mac, see these pictures. Those things, are mainly to do with whether your Mac is compatible and whether you have enough hardware resources to run the OS without too much performance loss.
First, you need to have the right hardware to support MacOS X:
1) You need a G3 or G4 processor (any speed). Although this is the official line by Apple, you can get a 604e processor Mac to run OS X 10.1, if you use XPostFacto, to install the OS. Be warned, it won’t be particularly fast!
2) Your Mac needs lots of RAM. Minimum would be 128mb, however you need much more if you want to use X with serious programs, and run them in parallel. Basically the more the merrier, I’d say 256mb or more.
3) You also need a lot of hard disk space. Three gigabytes or more would adequately allow you to install OS X, as the OS consumes at least 1gig of space! But you will also require disk space for all of your applications.
4) Your Mac also needs a reasonably fast graphics card. An ATi Rage 128 would be the minimum requirement, but a more up-to-date card would be better.

Next, you need to prepare your Mac for the new OS:
1) Make sure that you have updated the Mac’s firmware. This is very important, because an old firmware version will cause random crashes, no bootup, or the installer will refuse to install MacOS X. See the Software Update control panel.
2) Partition your hard disk, or buy another hard disk to install the OS onto. This is also important, because if MacOS X ever gets corrupted, beyond repair, you will have to reformat and reinstall from scratch again. I recommend that you use HFS Extended, not UFS, as this does not support data and resource forks. See picture for how to format disks.
3) Some G3 Macs will not allow you to install X on a partition bigger than 8 gigabytes, so I suggest you find out if your Mac suffers from this deficiency or not. Then create a special partition to install the OS and any applications onto it.

Installing X is relatively straight forward, and provided you have followed the on-screen instructions (the readme especially), and hopefully, all of my advice, then the process should be quite painless. Note that it normally takes about half an hour or so to install the OS, and on later versions of X, you might have to insert at least another CD, into the CD drive to complete the installation.

Once the installation is complete, you will have to restart the Mac, and you will be confronted with an auto setup application, that you have to complete in order to get into OS X’s Finder. Normally this covers internet setup, system preferences, and your User preferences. I suggest that you are setup for internet access as well, once the auto setup program finishes, as it will ask you if you want to send the OS X registered user info (name & address, etc.) to Apple. After you’ve done this, you are prompted to key in your password - it is very important that you do not forget your password, as it is a quite awkward to change it, once you’ve forgotten it.

Which Macs have the 8 gigabyte disk space limit?

If you have one of these Macs, and intend to install MacOS X 10.0-10.1.5 on it...

PowerBook G3 Series (excluding PowerBook G3 Series, with Bronze Keyboard)
Power Macintosh G3 Desktop
Power Macintosh G3 Mini Tower
Power Macintosh G3 All-In-One
Macintosh Server G3
iMac 233 MHz
iMac 233 MHz/B
iMac 266 MHz
iMac 333 MHz

...Then it has the 8gig limitation, that is, MacOS X must be installed within the first 8gig of the hard disk, ie. the total disk space is 10gig, so you make 2 partitions, one that is 7.99gig, and the other 2gig. Install onto the 7.99gig partition, as the other partition will not work as a bootable volume. Note that if you install on to an ATA hard disk, then it must be the master drive (ID=0).