Aoa Members,

Not being a student of history I am at a complete loss at the art of answering subjective questions. On some questions one can ride as many pages as are available, such as the Social Reform of the Prophet SallAllaahu alaihi vasallam. But some questions have a very short answer like 'fate of Tariq b Ziad and Musa b Nusayr after conquering Spain'. Can someone please guide as to how is one supposed to answer questions? What should be the length of answers? How to extend an otherwise straight forward response?