just open the Extensions manager control panel. You will be shown a lot of entries which you can sort by name. First you may want to disable some of the extensions like printer drivers you do not need (LaserWriter, Color StyleWriter Pro, etc.), all help files (if you are familiar enough with the Mac to do without them), Ethernet and EtherTalk (if you do not have such a network), QuickDraw 3D, WorldScript I and II. Then, disable some of the corresponding control panels (if you do not know which control panel corresponds to which extension, leave the control panel alone (they are not that big). You will have to restart your machine for the changes to take effect. Do not disable to many at a time (three or four) and write down which you have disabled before restarting, just in case you have to re-enable something...
Before and after a restart, check the memory usage (Apple Menu, first entry "About this computer") and pay special attention to the "Biggest free block" or so (sorry, my OS is german). It will increase when you have disabled something.
For Web surfing, you *need* most of the Open Transport extensions plus some control panels called PPP-something.
For your StyleWriter II, you can use the Color SW 1500 extension which is included in OS 8. This driver is for a color model, but it works fine with the StyleWriter II.
[This message has been edited by Walter J. Ferstl (edited 01-19-2000).]