It's probably the most interesting for players around 1500 or 1600.
Just have a look.
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 30 minutes of tactics per day. I provide 1,500 simple tactics problems for you to study, plus I also recommend some of the best tactics books.