Description in the past tense.
I am curious; if one was describing a person in the past tense in spanish (e.g., John had brown hair and was very tall) would she use the preterite or imperfect'
Christopher is far more careful when it comes to general statements than I am, but imperfect is generally the main tense to use in your case, in Costa Rica, and practically everywhere else.
I think it should be imperfect tense. As I understand it, the imperfect refers to the "general" past and the preterite to a "more specific" past.
John fue alto ---|> John was "suddenly" tall
Of course I'm just thinking out loud, let's wait for other opinions.
Was the action completed in the past (simple past -pretériito perfecto simple)? Does John no longer have brown hair? Is he no longer tall? Use the preterite imperfect. (pretérito imperfecto)