There are two things that keep Tauros at bay from the OU ranks, and they are Skarmory and Forretress. Both of them wall Tauros exceptionally well, and are usually so prevalent in OU teams that they, by themselves, have rendered Tauros almost obsolete.
However, if Skarmory and Forretress are absent from the field, it may come as a surprise that, similar to RBY, there isn't very much that will stop Tauros from just bulldozing through its opponents, especially if they have sustained any kind of prior damage. What distinguishes Tauros is the fact that it's so fast, meaning that whatever switches in will more than likely have to eat two Double-Edges before being able to act, and by then it may well be too late. When considering Tauros, be sure to have a solid plan to dismantle Skamory and Forretress, and should they be brought down, let the rodeo begin.
Tauros's Double-Edge is extremely potent; anything that doesn't resist it will sustain a pretty large amount of damage. Should the opponent resist or be immune to Double-Edge, hit it with an Earthquake; chances are it will be super effective. Should Tauros get low on health (probably from the large amounts of recoil damage it'll sustain from Double-Edge), use Rest to heal off the damage and continue attacking with Sleep Talk. Tauros also doubles as a nifty switch-in to Nidoking, as Tauros isn't weak to any of Nidoking's attacks. Tauros is a very simple Pokémon to use, but it is very good at what it does.
Body Slam is an acceptable alternative for that nice shot at paralysis should you need it. Fire Blast is a gimmicky option that will hit Forretress and Skarmory for a load of damage, but Tauros will be hard-pressed to give up any of its moveslots for such a situational move.
Checks and Counters
As mentioned earlier, Skarmory and Forretress will just about always wall Tauros. Forretress will take a really hard hit from Fire Blast, Skarmory not so much, but remember that to have Fire Blast, Tauros will have to sacrifice part of what makes it so good. Aerodactyl works very similarly as a UU counter; Aerodactyl also benefits from being faster than Tauros and can carry Reflect too to buffer Tauros's assaults.
Next in line is probably Starmie, but only if it has Reflect; since it's one of the only common Pokemon faster than Tauros, it only has to take one Double-Edge before setting up Reflect and healing off damage with Recover. Raikou can be used similarly, but since it takes a lot of damage from Earthquake and has to Rest instead of Recover, it can't switch in more than once or twice. Note that if Starmie or Raikou get paralyzed, they are no longer legitimate counters.
Other options for counters can include Pokemon with high Defense and/or Charm, Reflect, or Growl—Pokemon like Miltank, Umbreon, Donphan, and Suicune are examples—but remember that they'll take two large hits before being able to act. Even in these instances, Tauros is usually just a critical hit away from breaking through.