Mega-Absol
Elite Four No. 3
Catch five new Pokemon in every new area and don't level them to the stage of your previous Pokemon. My starter is my safety net... I HATE blacking out...
I don't really put much effort into making them harder per say, but for X I have banned all legendaries from my team as well as allowing only one Pokemon capable of mega evolving. Other than that I just use the Pokemon that I like and that is usually enough of a struggle in itself lol.
Go without the EXP share (ie turn it off) in this game as that's a large reason why it is easier. Avoid catching everything you see too as you get exp for catching stuff --> boosts levels that way. If you don't want to use the Amie too which can make battles easier too that's another thing... but that involves not using the Amie. =p (Ie cute interaction feature with your Pokemon).I'm looking to do a challenge run once my Pokemon Y comes in the mail, as I've heard that the game itself was pretty easy. I'm going to play the game on "Set" battle style for sure.
Anyone have any suggestions about how else I should make the game harder?