Its about a year since I started accumulating my Problems Worth Noting file. I solve several Problems of the Day each morning over breakfast and record the problems that I find particularly instructive. The problems of the day that I have been using can be found at:
http://chesstempo.com/widgets.html (Easy and Medium)
When I find a problem that I want to keep, I hit Alt/PrintScr to copy the window to the clipboard, and paste it into Paint. I use the crop function to cut out the board image and save the result to a file. About once a month, I paste the new problems into a word processor document, and add my solutions.
The criteria for inclusion are that the problem be simple enough for me to have a realistic chance of finding the solution in a clock game, but difficult enough to cause me trouble. There would be little value in simply recording the problems that I failed to solve, because many of these would be unreasonably difficult. (They could also have many solutions or no solution at all.) There would also be little value in recording problems that I solve quickly and effortlessly. I sometimes make a move or two before recording the position to make it easier.
About every six months, I work my way through the file, solving the problems, correcting my solutions, and adding comments to tell me how I could have found the solution more easily. I have just finished my second pass through. I currently have about 280 problems. (I do not have an accurate count because I have not kept a tally of the small number of problems that I have deleted from the file.)
I think this has been one of my more successful training exercises. It shows very clearly where I am falling down. My main failings appear to be:
* Failing to take stock of the position before I start analysing moves.
* Failure to look at all my first moves.
* Failure to follow all checks, captures and threats.
* Failure to check my solution.
My main failure is failure to look rather than failure to see. I tried hard to address this failure. My accuracy and speed did appear to as I worked through the file, at least when I was able to maintain the increased discipline.