For a look at de la Maza’s method from a respected chess coach read the following:
Rapid Chess Improvement: A Study Plan for Adult Players
I would suggest paying particular attention to the following observation: “Many players have tactical abilities far beyond their rating, but are positionally pathetic. Another thing that de la Maza didn’t mention (he was most likely unaware of it) is that
many tactical errors occur after a strategically poor position has been reached.” He also points out that even GM’s are subject to the same problem when they get a poor position strategically…tactical errors follow.
Many will disagree with this assessment but I’ve been saying all along that if you have a poor position strategically tactics are only going to be possible if your opponent blunders and allows you a tactical solution to your problem. The reason Morphy was so successful at pulling off brilliant combinations was because his positional understanding was so far ahead of his contemporaries that he achieved overwhelming positions which made the tactics possible.
De la Maza’s system may, or may not help improve your tactics. That’s not the point I wish to emphasize. It’s exactly as bjphillips’ good advice indicates. Too many times players think that once they reach a certain level that all it takes to move to the next level is more of the same. Like tactics study got me to 1600. More will get me to 1800. Wrong! It takes different skills to beat an 1800 than it does a 1600.