Flareon

Type Tier
Fire UU
Statistics
Stat
HP
65
333
Atk
130
358
Def
60
218
Spc
110
318
Spe
65
228
Name Moveset

Mixed Attacker

~ Fire Blast
~ Body Slam
~ Hyper Beam
~ Quick Attack / Focus Energy

He has decent HP for a Fire-type and the traditional low Defense, but trades a Fire-type's traditional high Speed (he'd be awesome at even 278 Speed) for a superb 318 Special and gigantic 358 Attack. In short, he's a powerhouse.

If you're playing on Stadium, the best strategy is to use Focus Energy and then Fire Blast away until Flareon dies or the opponent loses. Hopefully it's the latter. Unfortunately, Focus Energy doesn't work properly in any other environment. In that case, just use Quick Attack; it takes advantage of Flareon's high Attack, and allows Flareon to surprise faster Pokémon.

Other Options

Mimic is cool for getting a new move, like Earthquake. Substitute is nice for protection. Leer can lower something's Defense on the switch so you can hopefully OHKO or 2HKO it. Sand-Attack is risky, but allows Flareon to take down much tougher foes with some luck and works well with Substitute and Body Slam paralysis.

Opinion

Low Speed and Fire typing hurt Flareon in standard play, but he's a strong UU Pokémon who hits hard on both fronts. Strike fast and don't let the opponent know what exactly happened; just watch out for those Water/Rock-types.

Counters

In Standard play, the obvious counters are any Water or Rock-type and the ever present and frightening Tauros. If Flareon is being used in Underused play, the list of counters remains similar. Again, any Water-type or Rock-type can immediately shut it down. Omastar and Kabutops are sure-fire ways of countering Flareon in UU since they are 4x resistant to Fire attacks and 2x resistant to Normal attacks, which make up the majority of Flareon's movesets.