More on beating Napoleon
Sure, there's a lot to say on why Napoleon lost at Waterloo beyond just that he was defeated by Wellington. But the French Army had already been driven back to Waterloo at that point. Wellington and the British Army drove the French Army all the way back to France from a tiny strip of land on the West Coast of Portugal.
Napoleon had swept all of Europe, handily defeating the Spanish and Portugese, before finally hitting the wall that was the British Infantry. Napoleon used his infantry to march en masse over other armies. Other armies broke and ran at the sheer mass of Frenchmen. Since his army was a conscript army, Napoleon simply accepted the losses it took to overwhelm his enemies.
At that time, the English were the only army to practice with live ammunition, and were the most well disciplined army in the world, able to fire and reload their muskets faster than anyone. When Napoleon met the British, he met his first fully trained enemy. The British lines, by and large, did not break, and their "platoon fire" decimated the French army. Platoon Fire: the line of infantry fired in sequence, by platoon, with the first platoon reloaded and firing by the time the last platoon discharged.
In addition to their lines of muskets, the British also used rifles, which Napoleon thought were a waste of time. At the time, infantry used muskets, which could be reloaded quickly (easy to shove the cartridge down) but were inaccurate. If you fired a bunch of muskets together, all pointed in the same direction, the effect was pretty good, though. Hence, the what seems to us strange strategy of lining up all together and firing all at once.
When your main infantry strategy is to simply overwhelm with sheer numbers, it doesn't make sense to take the time to train someone to use a slower loading, more difficult to handle weapon like a rifle. So Napoleon dismissed the Rifle as an ineffective weapon for war.
The British Army, however, already had a culture of rigorous training and used live ammunition. The latter would be an important value to have if you're going to think about using a rifle, the whole point of which is to get good at hitting something. With a musket, all you need to be able to do is reload quickly and point in the right direction. You can practice this without ammunition, as many armies did. The British saw the importance of getting used to the explosive noise, kick and smoke generated by firing the things. But with a rifle, it's even more important to use live ammo, as you'd better be able to check if you are, indeed, hitting something.
The British created Rifle Regiments who would range out in front of their lines as the other army's infantry lines approached. The Rifles would pick off officers & noncoms so that when the two lines of muskets finally met, the other army would already have lost its leadership.
I think that these two approaches to war say something about the two cultures who were clashing. And I think that the British won because their culture's values shaped their - superior - approach to fighting.
I am indebted to Bernard Cornwell and his series on the fictional Richard Sharpe, who, like his naval counterpart, Horatio Hornblower, educated me in the Napoleonic Era British Army values, tactics, and battles. I am also indebted to Joe Moore, who told me, repeatedly, that I would like Sharpe & his adventures. He was so right!