After many years of thinking about it, I finally took the plunge and started guitar lessons, prompted by my wife. The first couple of weeks are excruciatinly painful, but now it is getting better. My fingertips of my left hand are getting nice and calloused. And despite the title of this post, my fingers aren't bleeding.
I found some good resources on the net that include instructional videos and suggestions for practicing.
The hardest thing about guitar is being able to switch between chords with speed. I found a good method to help with this: each practice session, practice switching between two chords as fast as you can, counting the number of switches you can make in one minute. Keep trying to increase the number each session, beating your score. Once you can get to switching chords once a second, you have arrived.
Needless to say, I am in the 7-9 switches per minute range and half the time, the chords sound awful, with lots of twanging and dead strings because my fingers are out of position. But I have seen improvement already and look forward to trying to best my score.