The key to chess improvement is pattern recognition.  Whether you realize it or not, to improve at chess you must reprogram your brain to see things that you did not see before. You can do this by studying at least 20 minutes of tactics per day.

On the site 'How To Get To 1900' you'll find 1,500 tactics problems for you to study and a system for memorizing openings.

You'll find it all explained on this brief review of the research that has been done on chess and cognition.