The easiest way is to choose a Linux distribution which doesn't suffer from bloat in the first place. Debian and Slackware will install a rather minimal system to begin with. In the case of Debian, you may then use the package manager to build it up from there. Of course, you can do the same with Slackware but your choices are more limited. There are many other choices, but they are a bit off the beaten track so support will vary. (Crux comes to mind, because they also support the PowerPC.)
Unless you are going for a specialty Linux distribution, which will be more difficult to setup and manage in most cases, you may get better performance out of FreeBSD, NetBSD, or OpenBSD. I have a slight preference for FreeBSD because it is very well documented: just look at the FreeBSD handbook or FAQs and many of your answers will be questioned. But FreeBSD doesn't support the PowerPC or 68k, so NetBSD and OpenBSD will be better alternatives if you want to experiment on your Ami or Mac. :-D For NetBSD and OpenBSD, a good minimal install is base and etc. If you want a GUI, add most xbase, xfonts, xserver, and xshare. Most of the fancy stuff will be in the ports collection, but there are a few other packages in the standard install which you may be interested in (development tools, text mode games, etc.).
If you really want to role your own, try Linux-from-Scratch. It is time consuming, but you will learn a lot about Linux!