We all have favorite words and phrases. As oral communicators, that's fine (until your significant other or close friend finally says that you need to stop saying "like" or "you know"!) As writers, we have to be aware of those pet phrases and try to eliminate a majority of their occurances in our work. If you're lucky, your editor will not only spot the recurring words or phrases, but will help you find ways to work around them, rewrite them, or even delete them.
It's always surprising to see experienced writers, as well as editors, fall prey to this trap. I do it myself, even though I'm aware of my key phrases and words. One of them is "key." Another is "as well as."
I'd suggest that you not try to correct this habit while writing your first draft. Write to your heart's content and don't worry about picking and choosing words while getting your story onto the page. But when you go back over your manuscript, attune your radar to be aware of words that recurr. Especially if the word is an odd one. The word "egregious" doesn't belong in a novel more than once, unless it's used in dialogue to signal a character's persnickety way of speaking.
Obviously, common words can recurr hundreds of times in a manuscript without raising any eyebrows, however, even using a word like "but" too often, especially at the start of a paragraph, will start to annoy readers.
Be glad you have modern software tools like "find" or "search" for seeking out word repetitions in a manuscript. Back in the day, we had no choice but to employ a highlighter pen and a lot of patience.
Something else I'm frequently seeing in manuscripts is the overuse of "thought verbs," like the words "thought" and "remembered." Readers of my blog, and fans of Chuck Palahniuk will have heard this advice before, but you can't hear it often enough: using too many thought verbs is a bad habit that slows down your writing.
If your character is remembering how she and her former flame spent their evenings, you can just write: "The evenings they spent, sitting on that dock..." You don't need to write: "She remembered the evenings they spent..."
Write things a reader can see, in their mind's eye. Remembering isn't visual, or very active. Neither is thinking, or realizing--or, God forbid, contemplating.
Just put us there. Trust us. We'll get it.
There's a place for thought verbs, but we devalue them by overuse. Same with your favorite words. Be ruthless.