After logging long hours at study sessions and finishing countless practice tests, it's important to culminate your study efforts with a well-planned test day. Scrounging for your coat at the last minute or grabbing a candy bar for breakfast isn't going to help your chances on the test. After all your hard work, you deserve a better finish than what that kind of morning will provide.
When does the test start? Where is the test located? How do you get there? What materials should you bring? Make sure to consider these questions well before the test day. Whether it's driving to the test location or picking out your clothes, simplify every step of the process that could potentially cause a stressful distraction.
Also, your mother was right: Eating a good breakfast is a big deal. Be sure to eat a healthy, balanced breakfast with proteins and complex carbohydrates for long-lasting energy [source: ManhattanGMAT]. And bring a water bottle and a healthy snack as alternatives to candy or coffee in case you get hungry during the day. A classic peanut butter and jelly sandwich, bag of trail mix or couple pieces of fruit will do the trick.
As far as attire goes, be comfortable. Old sweatpants, sweatshirts, flip-flops and slippers may not be appropriate for most outings, but if that's what's most comfortable to you, wear it on your test day. Remember that the testing center may be warmer or colder than you anticipate -- wear layers to keep yourself at a comfortable temperature.