休斯敦领事馆 is small. Be prepared before you go. Make sure you have all required documents, including photos, money order and self-addressed/stamped UPS if you don't have a friend in Houston to pick up it a few week ago. I don't understand why we need to be there in person. In fact, no interview is needed at all. It is really boring, time/cost-consuming...... Anyway, if you have a friend in Houston, get his help, no matter how long you haven't contact him. Believe me, it will let you much easy. Otherwise, you need to prepare well.
Good luck