I have three tips, not so much what's on the computer, but who's on the computer. I have seen people do these things, bang their heads on the table, and only change their ways after lengthy education.
1. After starting your computer up wait until all the startup processes are up and running before you start clicking on stuff. Yes, you want it to "go," but your goal will be reached more quickly if you just wait a couple of minutes (get a cup of coffee or something).
2. Limit yourselves to minimal applications running at the same time. I often get complaints of a "slow" computer that has upwards of 15 applications running.
3. Don't get "click happy." I see users who will click, and click, and click...if the application does not appear instantly. Every click is a command to your computer to do something, so multiple clicks for the same application will only slow it down.
These are the most common offenses I see others committing...I tell frequent offenders of no.1 to open taskmngr to "performance" and to touch nothing until it's stable at 0%-4%.
...and I hate to stereotype, but my mother and g/f are the worst offenders of no.3. They'll click a CPU to death.