Here's a technique that you can use before or after writing a scene to make sure that it really comes alive. I call it the Roshomon technique, after the classic film that showed an incident from several different viewpoints. Here's how it works:
First you imagine the scene from the viewpoint of your protagonist. How does he see the setting? What would she notice in this location? What would he hear? What would she smell? What feelings would the setting and situation evoke?
Then you imagine the scene again, from as many perspectives as there are characters, including minor ones (for example, the waiter who is serving your main characters dinner).
When you've done this and write (or rewrite) the scene, you'll have a lot more details to choose from and the scene will come much more vivid.
PS: This technique isn't in my new book, but lots of others are: Your Writing Coach, published by Nicholas Brealey and available from the usual online and offline sources.