Drapion is most effective when utilizing its Speed, bulk, and power to sweep with Swords Dance. Setup opportunities aren't hard to come by, as Drapion can force out Pokemon such as Rotom, Slowking, and Mesprit quite easily to pick up a Swords Dance. Once at +2, Drapion is able to 2HKO nearly every Pokemon in the tier, with even defensive behemoths such as Tangrowth, Steelix, and Poliwrath falling to Life Orb-boosted assaults. Crunch is Drapion's main STAB move that gets pretty good neutral coverage on the tier, and hits the many Psychic-types in the metagame for super effective damage. Earthquake hits a lot of things that Crunch doesn't, including Steel-types and opposing Drapion. Steelix and Ferroseed don't take +2 Life Orb-boosted Earthquakes that well, and Earthquake also gets the crucial OHKO on Aggron.
The last slot can be a tough decision, as both moves are very good and have a lot of use in the current metagame. Poison Jab is the superior choice to make Drapion a more potent offensive threat, as it OHKOes Tangrowth at +2, and 2HKOes Poliwrath after Stealth Rock, although the latter will phaze Drapion out before it can land a second blow. Poison Jab is also good for getting a guaranteed OHKO on Grass-type threats such as Lilligant and Sceptile. Taunt, on the other hand, ensures Drapion's longevity isn't cut short by status, and prevents Pokemon such as Slowking, Rotom, or Uxie leaving it with a parting gift of paralysis or burn. Poison Jab is generally better, but Taunt can still be useful for setting up to oblivion on certain threats.
Maximum Attack and Speed is used so Drapion can hit as hard as possible while Speed tying with other base 95 Speed Pokemon, as well as outspeeding the likes of Rotom, Moltres, and Lilligant. Life Orb is generally the best item, as Drapion needs all the power it can get, and the HP lost is but a small price to pay, especially because Drapion looks to set up by forcing switches. Lum Berry is also a good choice, and it is especially useful to prevent status effects that can't be blocked by Taunt, such as a Scald burn or a Body Slam paralysis. A bulkier spread of 180 HP / 72 Atk / 252 Spe can be used in the hope that Drapion will be able to attain more boosts. Both Lum Berry and Black Sludge are viable item choices with this spread, and Taunt becomes a much better option. Sniper is the ability of choice, as Drapion isn't looking to take hits, it's looking to dish them out. There are some additional options that you can use on this set; Aqua Tail can be used in place of Poison Jab to hit Pokemon that Drapion would otherwise find it hard to get past, such as Rhydon and Steelix, but Poison Jab is better overall. Pursuit is also viable, and it allows Drapion to KO Pokemon such as Rotom that have the balls to stay in as you set up, but then are promptly destroyed as they try to flee.
As this set relies on forcing switches to set up a Swords Dance, entry hazard support is greatly recommended. As a bonus, it also helps Drapion get past its checks. For example, two layers of Spikes allows Drapion to OHKO Intimidate Qwilfish with a +1 Earthquake. A great partner to set these hazards up is Roselia, which has access to Spikes, has good synergy with Drapion, and can dispose of Drapion's checks while it sets up on many special walls and attackers. Grass-type Pokemon such as Sceptile work well with Drapion, and can break through Poliwrath, one of Drapion's greatest checks. Rotom is another great partner for this set, as it synergizes well with Drapion, beats Poliwrath, and weakens walls with Pain Split, allowing Drapion to take them down later. Bulkier variants can also go toe-to-toe with Escavalier, another one of this set's best checks. Clefable also partners well with this set, as it has access to Wish and Heal Bell to grant Drapion another chance at a sweep. In return, Drapion can force out Ghost-types such as Rotom and Golurk, which Clefable can't touch when they're behind a Substitute.