Just poll watchers isn't enough. You also have to get rid of the extremely sketchy mail-in voting process, get rid of impossible-to-verify electronic voting machines, and automatically register everyone to vote and make sure they have a voter id. Like I said: make the voting process so painfully simple that fraud is literally unimaginable.
While you're at it: you should probably also get rid of the whole structure of first-past-the-post and winner-takes-all systems. The fact that it is even possible to get full power over a country with just 23% of the vote is just embarrassing.