Easiest way to win duels

I've found that the easiest way to win duels in the PC game is to just stand still and keep casting Expelliarmus. Rictusempra isnt much help, because most of the time your opponent will rebound it to you using Expelliarmus anyway. Mimblewimble is of no use whatsoever. However, your opponent cant just keep blocking and dodging spells forever. Sooner or later, he or she will have to cast Rictusempra spells on you. All you need to do is stand still and keep casting Expelliarmus. True, your opponent will do the same and you'll will be playing a tennis match of sorts for a while; but eventually you'll score a hit. And a spell rebounded by Expelliarmus does far more damage than a Rictusempra hit.

This strategy only gets a bit weak in the later duels.