Becoming a better chess player is not simply learning about advanced strategies, it also includes learning about all aspects of the game including wasted moves. In the game of chess you only get so many opportunities to move your pieces and advance your strategy, so it is important that you use all of your moves as wisely as you can.
A wasted move is one that accomplishes nothing for you in the way of strengthening your position. If a move does not improve your defense or your offense it is wasted. Some inexperienced players will waste moves while waiting for their opponent to make an error and this is a poor strategy. Sometimes a player will move a primary piece forward without providing and defense for that piece. Then when the opponent threatens that primary piece, the inexperienced player simply moves the piece back to where it was. This accomplishes nothing and wastes two moves.
In becoming a better chess player the player who can control the board, especially the center of the board, has an upper hand in the game of chess. An experienced player understands that they need to make every move count and that each move should be accomplishing something either in the way of offense or defense. A very good player is able to use a move to help defend, attack, and control the board all at the same time.
Try not to allow your opponent to have moves that are more effective than yours causing you to waste moves. Since chess does not allow you to make many mistakes against an experienced player, try not to let wasted moves be one of the mistakes you make, particularly since it is a preventable error.