Make cool designs on the answer sheet...for example, fill in A, B, C, D, D, C, B, A, and so on for a whole section. There are other cool ones. If you are real artistic, make a smiley-face out of the answers for all sections. Then, instead of using the writing sample time to write a statement, fill in your real answers.
Seriously, I did mine one page at a time. For args, I did all the types of questions I found easiest in my first pass through the section, then did the tougher types on a second pass. At this point, I would fill in answers page by page...so 4-5 at a time. Finally, I did all the parallel reasoning questions, and filled in those, and for the easier types that I maybe just couldn't figure out, I filled in B for them all. For games or Reading Comps, I just filled in a whole game or passage worth at a time. Don't fill them all in as you go along....it takes up too much of your time that way. And definitely go in with a 'guess' letter in mind.