Doduo boasts decent Speed and Attack, useful STAB moves, and decent coverage, allowing it to function as a fast, physical sweeper. This variant of Doduo aims to sweep, clearing up weakened teams late-game with its powerful STAB moves, while relying on priority to prevent revenge kills by faster foes. Return is the standard Normal-type STAB move, and is a good one at that: with reasonable power, perfect accuracy, and no recoil effects, you will find Doduo using it more than any of its other moves, not only because it has a great deal of neutral coverage, but also because it is Doduo's most reliable attack. Double-Edge is a more powerful but also more risky alternative to Return; it can make the difference between an OHKO and a 2HKO, but lacks Return's long-term reliability. However, it is illegal alongside Brave Bird, and as Brave Bird does not have as reliable an alternative as Double-Edge has, it is usually the more worthwhile investment. For a secondary STAB option, Brave Bird is Doduo's most powerful choice, and as mentioned previously there are few worthwhile alternatives. Pluck is one, allowing you to steal Oran Berries from walls such as Bronzor and Gligar that come in to make your life difficult. While not as powerful as Brave Bird, it can make your life much easier should you happen to catch them on the switch, not only preventing them from healing, but also healing Doduo in the process.
Quick Attack allows Doduo to escape the priority death trap from Pokemon such as Croagunk and Machop that may try to bait Doduo into using Brave Bird, and also allows for an assured end to weakened foes that may be carrying priority. STAB Quick Attack from Doduo can really hurt, and can allow Doduo to act as a fairly good revenge killer. Doduo shares the pain of many Normal / Flying Pokemon in that the Steel- and Rock-types that inhabit Little Cup really make its life a trial, since they resist both of its STAB moves while being naturally very defensive, and Doduo has barely anything to hit back at them with. However, given the low Special Defense of most of the Rock-types in Little Cup, Hidden Power Fighting, even off Doduo's pathetic Special Attack stat, does a lot of damage to many of them, most importantly Aron, who 4x resists both of Doduo's STAB moves. Aron is OHKOed and other Pokemon, such as Onix and offensive Rhyhorn, are 2HKOed. On the other hand, Hidden Power Grass OHKOes Onix and Rhydon, as well as almost always OHKOing Omanyte and Kabuto, though it does not do as much to Aron. Hidden Power Ice is also an option if you are worried about Gligar, OHKOing offensive variants and almost always doing the same to defensive ones.
The EVs and nature are incredibly straightforward, with simple sweeper EVs for maximum effectiveness at its job, and a defense-lowering nature to avoid spoiling the power of Hidden Power Fighting. Naughty grants greater attacking power, but Naive grants greater Speed, which can make the difference between death and survival, though the choice is really up to personal preference. Ordinarily, 236 EVs would be sufficient to maximize both Attack and Speed on Doduo; however, due to the lowered IVs from using Hidden Power, 240 EVs are given in each stat to ensure that, whatever Hidden Power you decide to use, Doduo's Attack and Speed are always maximized.
Stealth Rock, despite being resisted by most of Doduo's counters, is as useful as ever to break the common Focus Sashes seen around Little Cup. Doduo is frail even without a defense-lowering nature, and taking into account Stealth Rock damage, Life Orb damage, and Brave Bird recoil, Doduo will not be surviving for long against a team that can potentially hit back. Rapid Spin support can help salvage some bulk, allowing Doduo to come in unscathed, and thus giving it more of a lifeline to hang on should it be struck by a weaker attack or require extra turns of Life Orb recoil in which to do damage. This cannot disguise the fact that Doduo is very prone to revenge killing, particularly from Pokemon such as Scarf Gastly or Scarf Cranidos, both of whom do not mind Quick Attack. You should make sure that you can deal with these threats to Doduo, as being unable to do so is often fatal to both Doduo and your team. As for what Doduo cannot take down through sheer force, Pokemon that resist its STAB moves are the main culprits, in particular those Rock- and Steel-types that do not mind Hidden Power Fighting. Bronzor is the best check around, and Doduo does not like being on the receiving end of a Hidden Power Ice or Psychic. To deal with it, you should take advantage of its sole weakness, Fire-type moves; Houndour beats Bronzor that lack Earthquake. Krabby can take any of its attacks and reply in kind with STAB Crabhammer, as well as easily taking on the Rock-types that also plague Doduo. In the case of Magnemite, Diglett can trap and easily OHKO assuming it does not use Magnet Rise on the switch.