Well, Wellington was a big fan of using reverse slopse on hills, both to portect his troops from unecessary fire and to hide his troop numbers. However....

 

Even at their best the rate of fire from cannons was not particularly high, nor was their aiming particularly accurate. recall also that most armies used a majority of solid shot that required a direct hit to be damaging. Colonel Shrapnel had just perfected the shell that would bear his name through the generations, even then his spherical case fragmentation device required great skill to cut the fuse to the correct length for it to explode over the hea dof advancing troops in order to spread the pellets below.

 

So really, the chief performance meter for napoleonic armies was rate of fire. The French developed the large phalanxed coloumn with supporting horse artillery which they betted could advance on, and break, any two file deep firing line before taking an unnacceptable number of casualties that would force the coloumn back.They were right for the most part.

 

At this point the success of British redcoats where others had previously failed becomes apparent. Draconian discipline and hour of drill had combined to produce in the british infantry a formidable firing line. The standard practice was to hold fire until within sixty yards, any further out was useless (as herald states)... other less disciplined european forces would have fired one volley uselessly by this point and would be reloading while the french advanced. Thus the British regiment would make their first volley count, their second volley would be discharged form the second file, and then the real trick of British musketry drill would come into play.... platoon fire. Firing by platoons allowed the British to relaod in quicker times, sicne they weren't constrained to the average pace of a regiment, or by the slowest man available, it was a less clumsy drill and thus afforded greater speed. As such a redcoat regiment could maintain firing rates of between 4-5 shots to the minute... more than double that of a Spanish regiment (for example).

 

Such a tactic required good judgement and nerves of steels form the commanding officer as well as very tight discipline form the redcoats in order to keep the rate of fire up. At the first signs of French wavering the British line would bayonet charge the french coloumn, which was usually enough to break the will of the coloumn and force the retreat. It was an incredibly succesful tactic. The French army's best hope wa salways to use it's vaslty superior cavalry to push line sinto squares, but even thent ehy were rarely succsesful.