T.1 - Characteristics
This question is an excellent candidate for a grid-style answer. A passing (upper Certified/National) example is given on pages 13-15 of Al Boyce's BJCP Exam for Dummies, located on the Resources page. Additional information and independent thought will be required for a Master score.
Troubleshooting is one of the main goals of a judge. Even if this question isn't on your exam, learning this material will push you to be a better judge.
30% - Describe
This can (and should) be listed in a bullet point format. Prose will take too much time. You will want to include every descriptor on the BJCP Scoresheet here as well as others you pick up throughout judging. For example, astringency would be described as "Mouth puckering, dry, harsh, unpleasant sensation in the jowls. Mouthfeel only. Can be tannic. Similar to sucking on grape skins. Often confused with bitterness."
40% - Causes / Controls
Most of the points are in this one section. Again bullet points here. You'll need to be able to show that you know all of the reasons why a particular characteristic is caused. For instance, cloudiness can be caused by a number of things. Additionally, chill haze is caused by different mechanisms than permanent haze. You should be noting that difference and any others like it.
30% - Acceptability
You'll be able to get a lot of points here for minimal writing if you know your stuff. Review the Off Flavor Flashcards below and memorize these.
Resources
BJCP Study Guide, pp. 59-63
David Teckam's Off Flavor Flashcards
The flash cards on the BJCP website have some minor errors in them. I printed these in 3"x4" size and carried them around for 4-5 months prior to the exam.
Brewing Better Beer by Gordon Strong, pp. 229-247
Thomas Barnes' Complete Beer Fault Guide
Recommended with reservations. This is entirely too in depth for the Written Exam. Attempting to recreate this on an exam will result in losing precious time for no additional points. Interesting read for the curious.