I like to install some plugins and extension.

Go Here and install NoScript and Here for AdBlock by clicking on Install Now and I like to install Fasterfox to help with the performance.

There are many other extension check them out.

I like tab browsing so I enable theses options:

1. Always show the tab bar.
2. When I open a link in a new tab, switch to it immediately.
3. I uncheck Warn me when closing multiple tabs.

Go Here to install a bunch of the common plugins you might need.