I've been typing with a Qwerty keyboard for almost my entire life, but I have never been very good at it. I couldn't touch type, but I still managed to get by with a mediocre 50-ish WPM with an awkward, three-fingered hunting and pecking technique. So, after purchasing a fancy new Razer Blackwidow mechanical keyboard a few months ago, I made myself promise that I would learn to touch type. I found this amazing website that had excellent Qwerty typing lessons. Once I finished those, I started practising on TypeRacer.com. I managed to get the average of my last 10 races up to about 53 WPM within a month of starting touch typing.
I was quite satisfied being a Qwerty typist until I started talking to an old friend about my touch typing experiences. He mentioned that he was interested in learning the Dvorak layout, but didn't want to deal with the hassle of it all. This got me interested in looking into alternative keyboard layouts since I had so much fun learning how to touch type on my Qwerty keyboard. After pasting some of my writing into this website that determines which layout would work best for you, I found out Colemak should be a good fit.
I installed the Colemak layout into Windows 7 and gave it a shortcut so I could easily switch between Qwerty and Colemak. I went through the TypeFaster Colemak lessons to memorize the layout. Then I started typing again on TypeRacer with a new account. I've been averaging about ten races a day since May 26, 2012. I don't type a lot besides the typing tests, although I do tend to get a little verbose on the internet from time to time. If someone used a keyboard for work, I imagine that their speeds would increase far faster than my own.
Anyway, my average typing speed is now about 73 WPM. I made a graph of my progress that you can see below:
I know that my speeds are not super impressive, but I thought that it might be interesting to see how a mediocre typist improves his speed over time.
The only tip I would mention to someone just trying out the Colemak layout is to completely forget about typing fast and focus on accuracy. If you have already learned how to touch type on a Qwerty keyboard, you will have learned several good typing patterns. Those good Qwerty typing patterns will now be bad habits you will need to break or work around with the Colemak layout. Typing deliberately and accurately is the only way you will overcome these challenges.