When playing a much, much higher rated opponent, it is critical to challenge him early in the match.  If you are a 1500-rated player competing against a 2000-rated player, you will likely lose.  If you play your normal game (statistically speaking), you don’t have a huge chance of winning.  This is the reason that you need to take some risk and CHALLENGE your opponent.
 
Assuming that you are a 1500 looper and your opponent is a 2000 looper, here are some possible ways of taking slightly more risk and challenging him…
 

 
 
Each year, you should take about 2 weeks and try to experiment with some new skills in your table tennis game.  During this time, instead of focusing on matches, focus on practice.  Try to play every day with a robot or training partner.  Here are some possible new things to try…
 
Distance. 
Instead of playing only 1 distance, try playing slightly closer to the table or slightly further back from the table.
 
Spin.
Instead of looping with the same spin, try to add slightly more or less spin to give your loops more variation.