To add onto what Nancy said, the destroyer is much like learning how to ride a bike. You'll fall a million times, but try and try again and you'll succeed. Someone on SDN told me to use the destroyer like a bible. So I did, I wrote notes in it, underlined, grilled every answer/answer choice until I understood why. Then one day, I got the hang of it.
I also went through it around 3 times very carefully, noting which answers I frequently got wrong, even though I knew the answer 2 weeks ago (you'd be surprised at what you forget). Then I made a list of all the questions that I got wrong and polished off those ones specifically
Needless to say, I was improved on my second DAT