if your stuck below 60wpm then thats not too much of an issue as thats plenty fast enough to get stuff done, if you were stuck at 40 then you would have a bit of a problem
^^^ This.
While I was ~100wpm Qwerty, I'm just fine and happy at 70wpm Colemak.
It's fast enough for me that I can express my ideas without getting frustrated at apparent lack of speed or stumbling over myself etc.
Am I upset that my speed is 30% slower than my old Qwerty speeds ? Not at all. If I was a journalist, then maybe it'd matter.
I imagine my speed will increase as time goes on, but since I'm comfy now, I won't actually do any drills / etc heh. Such a slacker :D
Others mention typing tests / common trigrams, etc. Another way to improve your speed is to get into pointless flame bait wars / arguments over the internet. Typing fast / yelling faster / louder than the other guy is a great way to get practice in ... even if a bit troll-ish heh.