As far as I can tell, no one pays much attention to the "Fixing the Paragraph" portion of the Writing section. Given that I pretty regularly get 1 or 2 wrong, I asked Erica Meltzer to spend some time with me on this.
You can read her method in this blog post.
The take-aways from the session for me were:
1) Skim. This is "Critical Reading Lite" meets "Improving Sentences."
2) On first read, mark anything that sounds funny. Chances are there will be a question related to that area.
3) Eliminate answers in the same way you would in the Fixing the Sentences section (i.e. Gerunds are bad; Shorter is better; Passive is bad).
Below is a Fix the Paragraph example from a Writing section. I got everything right, except for #31. If you'd like to see the other questions, they are on pages 535 and 536 in the College Board Blue Book.
Illustrations by Jennifer Orkin Lewis