How to measure my progress

In the last days I thought about the question how I can measure my progress.
After all the playchess rating is just a blitz rating. I do not have the time at the moment to play a lot of real tournaments so the progress is quite difficult to measure. So I decided to compare the improvement that I hopefully achieve measured by different methods.
My rating at playchess was 1538 when I started the program. My rating on the chess tactics server was 1450 and my Fritz rating was 1735 after 20 games (blitz).