Hello everyone! I thought I would chime in about my learning experience so far with Colemak and join in with others who appreciate it. It's a pleasure to meet you all, and you're welcome to call me "James" if you like that better than this ancient username.
Upon learning of Colemak's existence, I had been a QWERTY typist for some 14 years. It wasn't so terrible, I thought, and flying at around 100 WPM on average was nothing of which to be ashamed. It wasn't until I had the ability to construct my own keyboard from scratch that the thought of a more efficient layout even dawned on me, and down the rabbit hole I went, starting with embracing an ortholinear layout and a non-standard arrangement of keys. I tried a lot of tweaks and personal changes to Colemak and Workman (thinking that I knew better than their creators what my own needs would be in typing) and finally retreated back to the comfortable, far less desirable QWERTY after a month or so. No matter how much I loved the changes, it was taking too long to commit them to memory, and I wasn't getting nearly enough dedicated practice time.
Much of the reason for that hasty retreat came from the fact that there was so much to take in, I wasn't thinking about the practicality. You're not just getting a new layout with Colemak, you're opening the doors to a whole new way of thinking about how you work and how you can make every aspect more efficient, elegant, and enjoyable. While that is wonderful when you have plenty of time, it's not so great when you have to type as part of your job every day. I had to live with feeling like a quitter for awhile.
Recently (about two weeks ago), there was a lull in my workload, so I decided to stop messing around with the mere idea of Colemak and commit myself to it. 30 WPM on TypingCat became 40, then 50, and all the way to 70 at one point. Now, much to my surprise, I'm not "thinking in Colemak" very much - I'm doing a lot of it without the need to think. What a rush!
There are a few tips that I'd like to share for those that might have started off like me and aren't afraid of tweaking their layout:
1) You may know your own needs and preferences right now, but remember that you can learn and grow to fit an existing layout. Slight changes in the layout may sound great, but you may not know the rationale for the layout well enough to make useful changes. Worse, you end up as an "island unto yourself" when you have an all-custom layout. If your changes are shared by no one, the resources to help you along are slim.
2) An hour or so of practice after work each day can give you good results if you stick with it. It's far better to give yourself a manageable practice schedule than to practice for hours only once in awhile.
3) The whole paradigm of keyboard entry as we've had it over the years has limitations. As is, traditional keyboards will never duplicate the fastest steno speeds or be without some flaws or quirks, no matter how optimized the layout may be. Don't set the bar at some nebulous vision of "perfect" and expect that, somehow, you will one day find what you're looking for.
4) 60 WPM is as fast as most people will ever go, and the average speed is usually lower still. Don't be frustrated if that seems to be your upper limit for awhile, even if you're used to typing much faster. It's fast enough to get serious work done and no one will bat an eye at the office.
And so ends my long spiel. :)