Pokémon X and Y Walkthrough, Pokémon Move Sets: Dragonite
(Please note that the recommendations below are largely made for in-game play. A Dragonite in a competitive environment will likely make use of different moves to accommodate for smarter, more adaptive opponents. If you have a different set of moves for a Dragonite, feel free to share them in the comments.)
Dragonite is the stuff of legends in the Pokémon world. If there's one creature that really stymied players of the first generation of games, it's the Dragonite owned and operated by Lance. Ever since they've remained beasts among beasts, and though there are now more options to fell a Dragonite it's still a risky task. Imagine what power you'd wield having one on your own team...!
Type: Dragon / Flying
Dragonite the mighty starts off as a lowly little Dratini, likely fished out of a pond somewhere. Level Dratini to 30 and you'll have a Dragonair; keep going to level 55 to receive your full-blown Dragonite.
Bug, Fighting, Fire, Grass, Water.
Dragon, Fairy, Ice (4x), Rock. Immune to Ground.
A quasi-legendary? You'd figure this thing would have good stats, and you'd be right. Almost all of its stats are above average. Dragonite's Attack stat stands out as one of the best you'll find among non-legendary pokémon, looming even over its impressive Special Attack. Defense and Special Defense are both fairly high, with Special Defense standing slightly higher, and both are helped along by a hearty amount of HP. Dragonite's only weakness is its Speed, which is still average.
Inner Focus: The pokémon is immune to flinching. Not that big a thing to have, really, though it comes in handy on occasion.
Multiscale: When the pokémon is at full health, any damage-dealing moves used against it will do only half damage. Easily the better of the two abilities, and well worth getting. Your Dragonite is almost always ensured to live past the first hit, which, given its quadruple weakness to ice-type moves and middle-of-the-pack, is very handy. This is a hidden ability.
Though Dragonite has a definite edge in Special Attack over most other pokémon, you should focus on physical attacks. Laden it down with a variety of attacks that will allow it to sweep the competition. Outrage is well and away your best choice for dragon-type moves, and can wipe out enemy pokémon teams almost effortlessly. Besides that you can give Dragonite moves that will fill cover gaps in your team: Fire and Thunder Punch are both good, Earthquake is fantastic, Aerial Ace is handy if you want to undo evasiveness, and Waterfall can prove surprising. There are plenty of options. Consider using Dragon Dance at the beginning of a battle to ensure that your Dragonite always goes first and always kills with its first hit.
Dragomite also has the capacity to irritate the other team, and I personally prefer having at least one support move. The standout favourite here is Thunder Wave, which is great if you're facing a fairy-type and don't think you can beat it in a single turn. Dragon Tail is a lot of fun for doing damage and forcing switches, particularly if you can get your Dragonite to go first, and Roost greatly boosts survivability.
EV / Super Training
Your Dragonite is going to have great stats no matter what, and will almost always hit hard. Consequently, I advise working on areas where it's a bit weak, namely its Special Defense. If you can boost this stat and pair it with Multiscale you stand a good chance of surviving a use of Ice Beam, which is probably Dragonite's worst nightmare. (Blizzard possibly, as well, though its poorer accuracy may save your Dragonite instead.) Speed comes next. Focus your remaining EVs on Attack.
Catching a Dragonite
You don't have too many opportunities to snag a Dratini or a Dragonair in Pokémon X and Y. The only place you catch these dragon-types is on Route 21, via a fishing rod. Pull out a Good Rod for a Dratini or a Super Rod for a Dragonair. In either case you'll be fishing for a while, as they're relatively rare.