When I took the LSAT for the 1st time, i was expecting to do really well because I always practiced really well. But on test day something really unexpected happened. In my first section i got to a question that I could not figure out so after a minute or two i did the smart thing and skipped it. However, this skipped question stayed in the back of my mind for the remainder of the section and it really distracted me from answering the questions that were in front of me and caused me to run out of time. After the section, all that I could think about was the blank answers and the missed section. During the next section, my mind kept wandering from the section in front of me to my overall score; how many did i miss? how many can i afford to miss? what is the experimental?
From there the thing snowballed and I ended up getting a score that was equal to my diagnostic (why i didn't cancel is not important). Of course, as it turns out the first section was experimental! And the question and then the section the I obsessed over did not even count.
The tip is STAY IN THE MOMENT. This sounds so obvious, and I would have thought so too going in. I am not a nervous person, I always had performed well on exams. But something about the magnitude of the test on my expectations got into my head the second something went wrong. Don't let that be you.
If you dont know the answer to a question, take a guess so you have something filled in and circle the question. Come back if you have time. But move on and move on MENTALLY. The one question you missed is not worth thinking about at the expense of the rest of the section or the exam. Stay in the moment and give your full concentration to the question that is in front of you. If you blow a section, ASSUME that it was experimental and move on. You can figure it out later. The best way that you can help yourself is to mentally move on.
Don't think about what section is experimental, how many questions you can miss, what section is experimental, what school you will go to, or any other big concerns. STAY in the moment.
Luckily for me, my story had a happy ending on my retake

Best of luck to the June 2011 crew!