Sir Arthur Wellesley, Chief Scout
My evening reading these days is broken into books and articles about: the New York campaign during 1776-77, the British invasion of Portugal in 1808 and anything about the early years of the World War 2 on the Eastern Front.
From my Napoleonic reading last evening I learned that Arthur Wellesley's habit was to ride at the front of his armies and reconnoiter with his cavalry and light infantry ahead of the army. That seems atypical for commanders of the period and most modern commanders.
On the eve of Austerlitz Napoleon went outside his army's pickets with his bodyguard to try to gain some insight about the terrain before the battle but aside from this recorded moment, I can't think of any other 18th or 19th century army commander that did this as regularly as Wellington did.
In every Wellington battle, his use of terrain seems to be worth an extra brigade or two and always has a major impact on the result. It was a secret to his success and I suspect that the more successful military leaders throughout history shared this same interest in seeing the battlefield terrain for themselves.