Because mental traits and behavior tend to be more subjective, you should answer according to how you have felt and acted most of your life, or at least in the past few years. For physical traits, answer as objectively as possible. If you’re having a hard time doing so, try selecting the option that best describes someone physically similar to you.
If you developed an illness in childhood or as an adult, think of how things were for you before that illness. If more than one quality is applicable in each characteristic, choose the one that applies the most.