Umm... This forum is for Strategies and Movesets, right? I think Contests should be included.
I'm not a fan of Jamming moves when it comes to contests. I like using moves that appeal as well as possible. I suggest this moveset for a beautiful Milotic:
Milotic @ Blue Scarf (goes without saying.)
Surf
Rain Dance
Safeguard/Dive
Hydro Pump
Rain Dance on the first turn, since you usually always start 4th. It makes a great appeal. Then on the next turn, combo it with Hydro Pump to make a high appeal plus the combo it gets from Rain Dance. If you're not the first one to appeal on the next turn, you could use Surf instead of Hydro Pump, depending on how you predict the Pokemon before you to appeal. And of course, when in doubt, use Dive or Safeguard.
In short, I WOULD use these moves in this order:
1st turn: Rain Dance
2nd turn: Hydro Pump/Surf
3rd turn: Dive/Safeguard
4th turn: Rain Dance (or Hydro Pump if in case the crowd is up to its 4th level in excitement.)
5th turn: Hydro Pump (or Safeguard/Dive if you're the first to appeal on this turn. You're most likely to be hit be a Hyper Beam or a similar move to hurt your accumulated appeal points.)
Good luck to you