Sinnoh Remake
Games: Brilliant Diamond / Shining Pearl (Generation 8)
New ribbons: 1
Total ribbons: 88
Twinkling Star Ribbon
How to Obtain:
Have obtained the Contest Star Ribbon (From OR/AS or BD/SP) and beat the Pokémon League
Win the Brilliant / Shining Contest
If you have the Contest Star Ribbon from OR/AS already, you can get straight into the Brilliant / Shining Contest needed for this ribbon.
The BD/SP contests are somewhat different than contests from earlier games, There is only a Dance Stage in the contest, but you earn points in 3 different categories explained below. You don't need to maximize all categories to earn this ribbon, you just have to outperform the other contestants, in my experience a visual score of 80%, dance score of 90% and a move score of 60% will win most contests.
Visual
Condition: Condition for normal contests works the same as it always has, however the Brilliant / Shining Contest uses all of your stats (including sheen). So if your Pokémon has come from Gen 6 with maxed stats it will be helpful to feed them random poffins to increase sheen. As always Scarves will give a boost to your contest stats (you can equip any for the Brilliant / Shining Contest), you can pick them up in Pastoria.
If you haven't improved your contest condition before now, this video by Austin John Plays is a great guide for BDSP.
Ball Capsule: The Ball Capsule that you choose has just as much impact on your visual score as your contest condition, all stickers provide a boost to the Visual Score so make sure to fill a Ball Capsule completely. Stickers also give bonus score if they are the same type (i.e. Cool) as the contest you are doing. You can find where to get each of the stickers here and what contest type they give bonus for.
For the Brilliant / Shining Contest only the Show Master Sticker (Beat all master ranks with one Pokémon) and the Champion Sticker (Beat Cynthias rematch team) provides extra bonus. That being said you don't need to have a capsule full of positive stickers to beat this if your Pokémon has maxed Condition, just make sure to fill the capsule with as many stickers as possible. If it is still too hard, beat the league a couple of times and try again with some Champion Stickers.
Dance
With this category, simply perform the rhythm game and you will earn points based on how well you did, simple!
Move
In BD/SP you pick only one move going into a contest that you can only use once, and you will gain points in this category if you
Use it closely before/after the NPC use their move, so its best to wait for the NPC to use theirs first and you tag along after.
Use the same type of move as an NPC when they use it, this is basically up to luck so don't worry!
Use the move how it wants to be used (such as using the move when groove is high)
Most people have come to the conclusion that the best moves to use are ones on this list where Hype increases when groove is high with a Heart Gauge of 3, to get the most out of this move type, use it when the NPC's activate their own moves and when you have max groove(groove is the arrows on Pokémon that indicates you have hit moves on time). A move that is very common to learn from this list is Giga Impact and it can be bought at the department store.
Returning Ribbons
Sinnoh Champion Ribbon
Simply defeat Cynthia at the Pokémon League.
Effort Ribbon
You can get this ribbon in Sunyshore Market when you show a Pokémon with maxed EV's.
Contest Master Ribbons (6)
You can get these ribbons by beating each of the categories of Master Rank Super Contests (these ribbons are a prerequisite for the new Twinkling Star Ribbon, which is explained above and applies to these ribbons also).
Syndicate Ribbons (3)
You can get these ribbons in the Ribbon Syndicate in the Resort Area when you spend 10,000/100,000/999,999 PokéDollars.
Daily Ribbons (7)
You can get these ribbons from Julia in Sunyshore City (top right house) every day of the week.
Footprint Ribbon
You can get this ribbon from Dr. Footstep in route 213 when you show a Pokémon that has gained 30 levels since it was caught or received. There is also a list of Pokémon that are considered "Silent" that obtain the ribbon with max friendship instead.
Best Friends Ribbon
You can get this ribbon in Hearthome City when you show a Pokémon that has maxed friendship. This is different from the original method (maxed affection in Amie).
Tower Master Ribbon
You can get this ribbon in the Fight Area Battle Tower for defeating Palmer at Rank 10 in Master Class battles.