Cimorene

Oooh, well!

I think rococo and baroque churches, at least from what I've seen, are generally a bit more pleasing to look at and be inside of than palaces, but the contrast is interesting. Churches have a natural focal point and they also tend to have very high ceilings in the fanciest space, which allows the visual composition to spread out and sort of... Visually move around the space more. There are other rooms in palaces, and particularly operas, that are similarly suited to rococo, but a lot of rooms have a much larger footprint with comparatively low ceilings. Even a lot of creative use of windows can't fully compensate, and the gilt details become heavy and cumbrous without sufficient light, while the layout of a big space without a clear focal point reduces the ability of the gilt to create emphasis, especially if it's overused.

Sorry, that rambling didn't teach you what to look for!

Personally I love wallcoverings and light fixtures and yes, furniture, especially marquetry designs, carved wood, and (in general) the legs. Rococo marquetry is very very fancy, with individual objects often being imo comparable to paintings by a master. Light fixtures are a general (not just rococo) interest of mine, but palaces are probably heavier on unique crystal chandeliers compared with, you know, stately homes of the middle class and lesser nobility, where you get to see a lot of torchieres and wall sconces.

And when I say wallcoverings, palaces and churches are more likely to have incredible murals than wallpaper or fabric or hand-painted graphic motifs like you see in middle class homes. Tbh, in many respects I find so-called folk rococo and the slightly less fancy interiors of wealthy and noble homes that are a bit less grand than palaces more interesting, at least when it comes to furnishings and wallcoverings. But there's no question that the murals are usually much more exquisite works of art. Ooh, and also fireplaces, mantels, and masonry stoves (though again, that is less likely to be found in a palace than in a mansion).

Porcelain is also a great miniaturization of architectural trends, especially in big pieces like urns and vases, but also teacups and plates and the like. Though I suspect there's a lot of imported Asian porcelain in the noble and royal collections of this period in addition to the rococo stuff.

A very fun thing to look for is when neoclassicism starts to appear. It has a pretty substantial overlap with rococo and a gradual transition, so you start to see motifs from Greek and Roman antiquity incorporated into a rococo aesthetic after about 1750 I guess (but Wikipedia pinpoints an Italian forerunner even earlier), and then later lots of neoclassical designs still dominated by the colors and rhythms and compositions of rococo.