Here's a Tor speedup tip I just learned today.

You can edit the file /etc/polipo/config with leafpad or vi or some other editor.

Polipo handles the proxy-like features for Tor.

If you look in that config file you will find the lines

Uncomment this if you have plenty of memory

followed by lines with # marks in front of them.

Removing the # activates that line and the speedup was very noticeable for me.