How to make a slow browser go fast?
Changing my DNS settings to Google's DNS servers 8.8.8.8 and 8.8.4.4 seems to help a little but might not be the comprehensive solution I was looking for.

Procedure

Bottom toolbar > System Preferences > Network > Advanced... > DNS > + > 8.8.8.8 > + > 8.8.4.4

Or, via command line:

networksetup -setdnsservers Wi-Fi 8.8.8.8 8.8.4.4


The procedure is detailed here.