Basically this but I can't say anything about it. I won on the first try, but played it at Reborn-level difficulty, so I guess it isn't much to take pride over. I can imagine blood-thirsty sadomasochist psycopaths that take on Intense building strategies or stuff to take them out, but there are always some stuff to watch out for.
For example: in double battles, focus on a single opponent. Second: have at least a pokemon with advantageous moves, but not type. The leader will always have counters for types disadvantageous to them, like how in Reborn Shade has a Chandellure with Energy Ball covering the Water and Rock weaknesses of his Chandellure