Acquiring Stars and Colors for your Trainer Card - The following tasks may be completed in any order, with no regard to a specific event relating to a particular color. Stars are added by the completion of each event.

Defeat the Elite Four.
Win any one Master Rank Super Contest
Win 100 consecutive battles in Battle Tower
Earn a Platinum flag in the Underground (capture 50 flags)
Capture all 493 Pokemon (not including event-only Pokemon)

Unlockables

Black Card Earn Five Stars
Blue Card Earn One Star
Bronze Card Earn Two Stars
Gold Card Earn Four Stars
Silver Card Earn Three Stars

Extra Villa furniture

Unlockables

Chandelier Walk a total of 300,000 steps
Great Painting hatch 30 eggs
Guest Set Defeat a total of 50 trainers in the trainer cafe
Music Box Purchase Racks
Piano Defeat the Elite Four 10 times
Pokemon Bust #1 Obtain one silver print from the Battle Frontier
Pokemon bust #2 Battle at each battle frontier facility
Tea Set Purchase the Guest Set
Wall Clock Plant 50 berries

National Pokédex

Unlockables - National Pokédex Complete the Sinnoh Pokédex by seeing all 210 regional Pokémon, then talk to Professor Rowan in his lab.