Is there enough? Too much? The goal is have just crisp, clear description in order to set the scene in the reader's head–they can "see it." Ah, but that's not enough. Yes we need to see, but we also need to hear, smell, taste, and maybe touch it. Or feel like we could. One aspect of revision, then, should be you re-examining the quality of your descriptive writing. First drafts are often plot-driven and a bit thin in terms of the writing . In revision you can make sure you use, with reason, a fuller range of imagery. We have five senses. Use all that seem appropriate for the scene at hand. Make it "real." Make your scene play like a little movie in the reader's head. Good description can do that.
This is a trickier area of revision. It asks you to take a very close look at your prose, your sentences. "Syntax," defined, often has a lot of mumbo-jumbo about "the rules of orderly grammatical constructions." For example, the main order of sentence is Subject + Verb + Object. Okay, we get that. But a better way to understand syntax is think of the order of your phrases and clauses. Below, is an example sentence from a chapter I just broke away from (my new novel):
1. "He became more flamboyant after his mother died, and his wild parties–for men only– were the talk of the town."
Okay. A solid sentence. Character development and conflict moving forward. But I kept thinking there was something slightly wrong with the sentence. So I revised its syntax:
2. "After his mother died he became more flamboyant, and his wild parties–for men only– were the talk of the town.