Optimizing Desktop Performance

I started looking for ways to optimize the performance of my Fedora 5 system, since it just have 256MB of RAM and my cheap boss does not have any intention for buy more. For example, while i am writing those lines, the memory usage was:

# free -m
             total   used   free  shared  buffers  cached
Mem:           217    212      5       0        0      45
-/+ buffers/cache:    166     51
Swap:         1027     92    934

and I just have openned Opera 9 with 8 tabs, a terminal console and Gaim. At this point, i can not complain about the performance, but as soon as I start to open new applications, I see how the amount of used swap grows and my desktop becomes really slow. One interesting source of desktop performance is Tom Adelstein's series I, II, III, and the posts are a great complement of the articles.