So I got the Mew from the monthly event, but it's nature isn't amazing for the Pokemon...
How can I make this work and train it so it's at least decent and usable in battle. I mean, there has to be a moveset...right?
I found something on Smogon. It is called the StallBreaker set. http://www.smogon.com/dex/xy/pokemon/mew/
Taunt forces the foe to use damaging attacks and prevents them from boosting, setting up entry hazards, and recovering. Soft-Boiled provides reliable recovery for Mew, healing 50% of its health. Will-O-Wisp is another utility move which burns physical attackers and cripples them by halving their Attack. Knock Off prevents Mew from Struggling if it has been Taunted and additionally removes the foe's item. Psychic can be used in the fourth slot for a more powerful attack than Knock Off, as it is boosted by STAB and hits Pokemon such as Keldeo and Mega Lopunny for super effective damage, as well as Pokemon such as Clefable and Mega Venusaur, which is important, as they're two Pokemon Mew is supposed to beat. But, Ice Beam can also be used in the fourth slot to beat specially defensive Gliscor along with Landorus-T.
Nature: Careful/Calm Ability: Synchronize Item: Leftovers: Move 1 Taunt Move 2 Soft-Boiled Move 3 Will-O-Wisp Move 4 Knock Off/Psychic