Happy OS rules:
¥ 1) remove all printer drivers you don't need, remove desktop printing altogether if you don't print things often - this does apply to the 8100 now... :-) Desktop Printmonitor and the Desktop Printing extensions. Get rid of Apple Colour SW PRO CMM (or something close to that - it's only for colour stylewriters anyway)... if no need for printing exists, still leave in: LaserWriter, Printing Lib and PrintMonitor.
¥ 2) yeah, this is a fairly standard caveat, but one we all ignore from time to time (and even if it didn't look like it caused any problems, it _can_ cause prefs corruption leading to problems way down the track that you'd never normally trace to the installer's fault) - if installing something, Boot Up Without Extensions, unless explicitly told to leave extensions on for the updater. (rare, but I've seen it)
¥ 3) Things that go trashwise if they appear in control panels or extensions: Macintosh Easy Open (leave MacOS Easy Open, tho), Apple Events Manager, Object Support Lib, StdClib, Sound Manager, Threads Manager, [ Memory Manager (unless OpenDoc is installed, in this case only, leave it there) ]
¥ 4) Keep an eye on your AppleScript version after installs - I've seen bunches and bunches of installers replace os8's applescript with the older version, and it breaks really badly.
¥ 5) If you have Scripting Additions folder in extensions folder, merge the contents into the one in the system folder, keeping the ones in the system folder:scripting extensions in preference.
¥ 6) All those things Photoshop installs in your system (including the startup item) are really useful if you have a $40,000 imagesetter and linotron output card. If you haven't, though, they're doing jack shit, but taking up memory and process time, and patching traps that don't need to be patched otherwise.. :-)
¥ 7) after installing anything, throw it onto "Crash Less Often" then pump it's memory up to the closest next multiple of 512k available (e.g. 1024, 8192, 16384 - If photoshop says "I want 15,000 kb memory", I say "you're getting 15360, and you'll like it, ok?") - DO run Crash Less Often over your entire system folder, but NOT while you're using it (boot up off another disk or something)... even the OS8 system has an incorrectly set CDEF. :-)
¥ 8) open up copies of your finder and system in resedit - in the SIZE resource (there is only one resource present in each, as they don't have the application interface), pump up the finder to wanting 1.5mb (1572864 bytes) for the preferred amount (the top one) and leave the bottom one (minimum - it's 128k which is such a nice number I'd hate to change it) The system file has 70,000 bytes set to it's min and preferred values - change this to 96kb (98304 bytes)
¥ 9) Create a 20-50mb read/writeable disk image with diskcopy. set diskcopy's prefs to _not_ verify checksum. name it browser caches and put it in your startup items folder. make two folders within this disk: Netscape and Explorer... then point your Netscape and Internet Explorer apps to use that as a cache. As a second layer of protection, delete your old cache folder and replace it (keeping the same name, of course) with an alias to the browser cache folder on the image in question. That way if one of the apps loses it's prefs for some reason, it won't just start using your disk again. Now you don't have IE and Netscape fucking around with your B-Tree. Just run Nortons over it (the image) occasionally, and you'll see how much shit you've saved yourself... :-) If it gets really fuxxored, just trash it and make a new one, or "erase disk" :-)
This method uses less memory and actually less system resources and processor time than doing the same with a ram disk. It's a little slower than the ram disk method, but stability is always my aim... :-)
¥ 10) (you're gonna hate me for this one) Don't use Speed Doubler. It is buggy. It has always been buggy, and will probably always be buggy. Use Motorola's LibMotoSh rather than Macuser's MathLibMoto (and never have them both installed)
¥ 11) Avoid VM if possible. If not possible, use real VM, and not RD. And only use as much as you need. VM is still one of Apple's nightmare areas.
¥ 12) use the default disk cache. just click the default button on the memory control panel if in doubt. :-)
¥ 13) If you use Apple Menu Options, turn off "recent Items" - I have seen this actually crash computers under heavy load, directly traceable to the control panel... If you use BeHierarchic (beta 10 or 11) and you haven't got recent items turned off, I'm surprised you even got this far... :-)
¥ 14) CMMs is one to watch for... just keep an eye on any you've installed, and if one looks like it's crashed you, remove it. (an old version of the custom icon remover one in TryGryve's CMMs had a bug like this at one stage)
¥ 15) Do have something to boot all your drives installed in your system during extensions loading time. (but only if you have more than one Hard/removable Drive) - either (but not both!!) FWB's HDT extension or SCSIProbe 4.3
¥ 16) As far as I can tell, CDROM Toolkit 3 is definitely a good thingª to have installed. :-)
¥ 17) get rid of stuff you don't use - that one comes under the common sense heading though... I mean, really, just how often do you _really_ use speech? Or AppleGuide? :-)