For the love of...

Most of these tips aren't going to speed up a Mac by any appreciable amount. Disabling dock animation and shadows isn't going to make OS X feel blazing fast.

Removing unused widgets and HP printer threads to free up real memory - yes.
Repairing disk permissions - no.
Clearing out Safari Favicons - yes.
Killing smart playlists - no.
Removing old apps - maybe if you're low on diskspace, otherwise no.
Disabling bluetooth - it'll save some battery life, but won't speed anything up.
Clearing autofill and history - no.

And for the love of God, if you're not an experienced user do NOT install Tinkertool or any other software like that. Apple hid those options for a reason! And despite what this list says, the gains you'll notice aren't going to be extraordinary.