re: How were the British so successful militarily?

Naval and economic power may be the primary answers but don't overlook the sneaky fricks at the British Foreign Office/Ministry. Their rumor-mongering and fake bank deposits planted a lot of distrust and animosity between Napoleon's officers but their masterpiece was the use of weaponized Islam to destroy the Sikh kingdoms of northern India and severely destabilize Ottoman Turkey. That al-Saud/al-Wahab alliance that still plagues us today was British doings.