Ah, sylveon. They’re wonderful pokémon, to be honest, and I congratulate you for obtaining one!
First, a warning. People will tell you that sylveon subsist on baked goods, and this perception is likely not helped by the fact that its evolutionary requirement involves whether or not it feels loved—a state most people achieve by feeding their pokémon poké puffs. However, while sylveon enjoy sweets, they should only be fed these sparingly. Their diet should consist of either sylveon kibble or, should you wish to give them a more varied diet, sylveon wet food, meat, and berries. Feed them more meat than berries, and you’ll have a healthy sylveon.
Other than that, many of the things you needed to give your eevee should also be given to your sylveon. This includes the same sorts of toys, chew bones for their teeth (which itself is a supplement to brushing)—even the same sorts of shampoo, conditioner, and brushes. (Just be gentler with maintaining your sylveon’s fur than you were with your eevee’s, as sylveon generally have finer fur than its preevolutions.)
The only other thing you’ll need is a ribbon clip. These are soft binds that can be put on a sylveon at night to keep their feelers from moving. Newly evolved sylveon are still getting used to manipulating their feelers, so in the early months, there is a risk that they may try to move their ribbons in their sleep. Clipping them together prevents your sylveon from wrapping them around its own neck—or yours.
In terms of non-material objects, sylveon are among the fairy-types who actually enjoy human company (largely due to its evolutionary requirements—sylveon literally cannot exist unless the bond it has with its trainer is strong), so you’ll very likely have little trouble bonding with them or getting them to follow your orders. If anything, you may need to be aware that your sylveon might just become possessive, jealous of your other pokémon, or overly affectionate. If any of these behaviors happen, be sure to establish boundaries with your sylveon and continue to help them bond with their teammates.
I wish you the best of luck with your new evolution, @artist-dreams. May the journey you take with your sylveon be a happy one.