That's a great question. First, I recommend reviewing your questions the next day and not immediately after you finish your practice test, this way you'll be more alert.
Next, you should look at the problems you got wrong and try to reason to yourself why the right answer is right before you look at the solution. Anyone can look at the solution and say "yep, didn't see that wall" and move on, but no learning happens. Take the time to convince yourself why the right answer is right, and then look at the solution. Your brain will have to force itself to develop spatial thinking, rather than just seeing the solutions. This is much more effective and you'll be learning much more from each test.
Also, this works with all the other subjects you're studying for too. Always look at the solution as a last resort or confirmation of your thinking, not as a go-to.
