If there is a contest guide already, Im sorry. If not, could somebody post some tips and useful pokemon w/ movesets. Thanks.

Not too syure which Pokemon could learn these moves, but look up a Pokemon that can learn a move that doubles your next appeal but has no appeal itself, and a move that double if used first. Use a Pokemon especially for contests, feeding ONLY the Piffins it needs, along with the corresponding scarf.
Use the doubler first. You will likely go first the next turn due to your lack of any appeal points. Then, use the "if used first score doubles" move. That's at least eight appeal points, which isn't too bad. That's 4 appeal points per turn, which is good since the basic appeal move is only 3 appeal points.
Hope you have good dancing skills too. Practice in game or other rythym based games, like Guitar Hero.
When it comes to dressing up, condition is key. Only feed your Pokemon the Poffin it needs to avoid filling in space of your Sheen bar unnecessarily. To find out which acessory goes with which category, check out lolstop. If you need more accessories check out Maity Square. The rarer the Pokemon (different region pokemon like torchic) the better accessories or berries good for Poffin making. You can also trade berries at the berry shop in Floamora Town.
About Poffins, follow the hints given by NPC, but try to mix with friends as much as possible; they taste better.
Gotta go, see ya and hoped it helped.