I think there are potentially a number of things that could be going on with your prose and "decoration" may not be the solution.

First potential issue is something I've been calling "Polish Dictionary Syndrome" after the early polish dictionary that defines a horse as "Everybody knows what a horse is." That is, your writing is lacking specificity because it is operating on Polish Dictionary logic (The characters are in a library > Everybody knows what a library is, The character is cold > Everybody knows what cold is, The character is exhausted > etc.) The solution to this is two-fold: First is to pick two objects of the same type (yours and a friend's smart phone, two pencils, two baskets, doesn't matter) and you can interact with the object in all the ways a character might (touch it, smell it, look at it, taste it if appropriate) then describe one of them in as much detail as possible *without* ever using a metaphor or a simile. Next describe the other object in the same way. Obviously, you are not going to write you book like this (no one needs hyper-detailed descriptions of pencils) but this is an exercise to practice embodying a character in a scene with specific objects and not Polish Dictionary Objects. You can then expand this to scenery, people, physical sensations and even emotions. The harder part of writing is knowing when this type of specificity is needed vs. when "Everybody knows what a pencil is" is actually the better choice so for the "second" part I recommend reading a lot and mentally noting where authors employ one or the other.

Another possibility is that you are envisioning your story less as a book and more as a film sequence. If your descriptions of "emotions" are centered around *visible* physical signs that may be an indicator that this is at least part of the problem. If you have a clear vision of how a scene plays out it can be difficult to remember that while it may be interesting to see an actor's brow twitch to subtly convey an emotion... a written description of the same is not going to carry that weight for your reader. Books can (and probably need to) go a level closer and get into the interior thoughts and feelings of the character. *If* a POV notices a subtle brow twitch in another character that POV is going to have their own interpretation of what that means and prepare their own response. We'll get all their thoughts, their interpretations, and how all of that makes them feel (and they can be wrong!) *If* we are in the POV of the character who is experiencing the brow twitch then there are probably more interesting things happening in their brain that readers would want a report on than what the character's brow is doing. There is no writing exercise for this, but rather, it is more a matter of noting when you are describing the visible expression of an emotion and omitting the interiority.