How to use the Tactics Trainer
Tactics are paramount, if you want to get better at chess. And Chess.com's Tactics Trainer is a great tool for helping you with this important training. However, instead of just bashing through thousands of tactical problems with the Tactics Trainer, here's a better approach, in 3 steps.
First, go to My Tactics Trainer. On this page you can see your tactics rating, how many problems you have solved and so on. Further, you can see your last 25 problems, listed chronologically, showing which problems you have passed and which you have failed.
Step 1
The first thing I suggest you do is this: click on the problem ID# for the first problem you failed. In other words, the problem failed closest to the end of the list. The problem will open in a new window. Now, click on "TRY THIS PROBLEM", and give it a shot. If you pass, click on the problem ID# for the next failed problem. If you fail, click on "SHOW SOLUTION", pay attention, then click on "TRY AGAIN", and make the right moves. Go through all the failed problems on the list, one by one. When done, it's time for a couple of minutes break, before the next step.
Step 2
Now it's time to work on some new problems, 25 problems to be exact. Why 25? Because that's the number of problems on the list of passed and failed problems. So, click on "START TRAINING!" on the My Tactics Trainer-page, and get to work, using the same approach as when you worked on the previously failed problems. Keep track of the number of problems you've tried. You can use pen and paper for this. Stop after exactly 25 problems. Take a couple of minutes break, then go to step 3.
Step 3
Now it's time to review your just failed problems. So, do as explained in Step 1, going through the problems you have just failed, until you get the them all exactly right (using "SHOW SOLUTION" and "TRY AGAIN" as needed).
Final notes
Following this approach you will highly increase the chances of storing the tactical patterns in your long-term memory. Each session (including all 3 steps) takes about 45 minutes, and it works great! Give it a try, and let me know what you think. 
