The official position is you have an hour for a taste retake. In reality bringing out a beer every 15 min tends to overtax the proctors since they need a little extra time IMO to fill out the much longer score sheet. For that reason I bring out the brews every 20 min so in effect someone sitting for my exam could have 80 min to fill out the sheets. In reality as an examinee or as a judge at competition you should be able to do it in 10 min or less or you are wasting time. Proctoring takes a little more time.
The key to a taste retake is to describe what you smell, see, taste and feel as descriptively as possible and then to describe what you don't smell, see, taste and feel. IMO on the exam the only place to speak about style is in the Overall Impression. However I feel for competition one should always relate what is sensed to style.
If, for the exam, one only focuses on what is perceived they really cannot be incorrect. The problem is many do not have the vocabulary or the ability to convey what is sensed. What I would suggest is to put down the description of something else you have perceived in your life experience. If is tastes like toasted marshmallows, instead of trying to come up with something clever, write that down. We all know the chances of someone putting toasted marshmallows in a beer is slim, but if that is what you taste, it is what you taste.
The one part of the taste exam you cannot control is score. The lowest score is 13 so I tell examinees to never drop below 15. The highest scores generally given are 45 so I tell examinees to stay below 42. Unless the proctors and examinees were trained by the same judge the scores tend to vary wildly and it makes that portion of the taste scoring (20%) a wildcard. The nice thing is at worst you will ever get on scoring is 9/20.
Keys IMO are:
Fill up the sheet with comments and no BS
Fill in the sheet 100% complete
Score as best you can
Be as descriptive as you can
Reserve any comments about style to the Overall Impression
I've been judging for quite some time, but when I took my taste retake I did not study at all. Just drove down 3 hours the morning of the exam and took the taste portion. IMO style is only important for the comments made in the Overall Impression.