How to speed up your joomla website

When I tried to update my website from joomla 2.5.17 to 3.2.2 through the admin panel THE SCREEN WENT BLANK!
I had no admin panel or website at all!
It was probably a bad idea to upgrade anyway, but now I had to restore a backup.
NONE OF MY SERVER BACKUPS WOULD RESTORE!
So now I was face with the backups on my own computer, some of them not simultaneous. I had several outstanding problems anyway, so I decided to try and fix them all at once: I had a jQuery conflict with cloudflare cdn, an indexing mod to index the notes didn’t work and the website was just too heavy and slow.
I ripped out all the content from the website database and reinstalled joomla 2.5.18 then related the content tables into the database.
Then I installed all the extensions I wanted, dropped the mobile theme which will be defunct soon anyway with joomla 3.3.2. To make the site superfast I used jch with all the switches turned on, smushed all the images and dropped the admin tools extension as soon I was satisfied I had secured the site.
Now I have a page speed score of 93%! Better than I ever achieved when I was using a cdn and there are a couple more things I can do to speed it up further.