1. multipurpose scenes (too often do i waste word count on characters just sitting around talking in ways that don't establish them, develop them, or really propel the story. those scenes are static and repetitive and could be doing more by implementing movement, tension, background, etc)
2. metaphors and other literary devices being used with intention and specificity (a very lazy example off the top of my head is describing a character in military servitude with the metaphor of being a doll — the idea there being that they are used and discarded like something inanimate. it's not bad necessarily, but there are other connotations around dolls that don't fit, like being dressed up and made pretty and things that might better suit a character in a role of domestic servitude. it would make more sense to say that the character in military servitude is a toy soldier, a prized trophy, etc. i would probably not use those because they're also lazy but the lesson is to be thoughtful with literary devices, and especially metaphors, because i find that i used to be kind of careless in just saying what sounded nice over what was more effective. how many people utilize metaphors of chess or cards with calculated characters like tom? i definitely have. did i contribute anything novel to his portrayal with them? probably not.)
3. just relax. not every sentence needs to or should be shakespearean. rhythm in writing is what keeps a reader's attention, and that can't exist without variety. if every line is some labyrinthine description of the lamp in the corner of the room, it becomes suffocating. your prose should serve the story, and vice versa. in my older writing, i find that my desperation to prove myself as a writer is so overbearing and distracting that it's hard to follow, and the story suffers for it. this isn't a "sometimes the curtains are just blue" thing. personally, the curtains are never just blue. i do think, however, that you can just say "the curtains are blue" and within context you've either already established or plan to later, it has just as much significance as if you wrote a full paragraph saying the same thing. most of the time, the lines that stick with me are the short, simple ones emphatically placed within the finer details. i don't know. think about amy march calling laurie mean. mean, instead of cruel, callous, unfeeling. considering the era of little women, those words fit just as well, but they don't elicit the same reaction, because mean is such an amy thing to say. it's sad in a childish way.
i used to post writing advice as it came to me but unfortunately the account i had it on was taken down and i had no backup for it. if you ever have more specific questions, i'm by no means an expert, but i'd be happy to (try to) help :)