Most club players can’t train 40 hours per week due to family commitments, school, job, etc…  However, most players can dedicate around 10 hours per week to improve.  For my personal students, I ask them to work hard to produce the best possible 10 hours that they can do.  I ask them to do 4 hours of matches, 1 hour of serving practice, 1 hour of physical training, 1 hour of video analysis, and 3 hours of training with the Newgy Robo-Pong 2050 robot.
 
Playing matches against various styles is an important part of a weekly training program because it “tests” your skills.  You should be able to properly regulate WHAT to practice based on how you perform in practice matches.
 
Serving practice is one of the fastest ways to improve.  If you can score 2-3 more points each game, that is a major improvement.  Even if you can’t win the point outright, a good serve should set you up for the next ball.  When serving, focus on keeping the ball low, with good spin variation, and good placement variation.  Try to develop a very similar motion while giving slight changes in the spin – heavy sidespin, sidespin backspin, no spin, and sidespin topspin.
 
Physical training is a vital aspect that every player needs to work on to move to the elite level.  At your current level, PT might not seem very important.  However, at the elite level, it is critical.  I would recommend focusing mainly on speed and flexibility exercises for the legs and core.  Top players say that 70-80% of their looping power comes from the legs and core (not the arm).
 
Video analysis is the most neglected aspect of training in the US.  Without visualizing of your strengths and weaknesses on a weekly basis, you are probably training incorrectly.  Record at least 1 session per week and take them time to watch it slowly while taking notes.  Ask a friend or coach to watch it with your and take a somewhat-critical approach to analyzing your game.
 
Robot training has helped me tremendously and I’m sure that it will help you too.  Instead of thinking about the score, you can focus on the areas of your game that really need to improve.  You can focus on making changes to your footwork, short game, blocking, looping, smashing, chopping, and serve return.  Start the drill very slowly with +50% wait adjust so that you can perform them correctly.  As you become more consistent at that speed, slowly decrease the time between balls by 10%.
 
Here is a sample training program from one of my students…
 
Monday:     Robot (1 hour) and Physical Training (30 min)
Tuesday:     Club (2 hours)
Wednesday:     Rest
Thursday:     Club (2 hours) and video analysis (1 hour)
Friday:     Robot (1 hour) and serving (1 hour)
Saturday:     Robot (1 hour) and Physical Training (30 min)
Sunday:     Rest