Filler words creep into everyone's writing. It's hard to avoid them in first drafts when you're intent on getting the story down, but you should weed them out as you edit. What I mean by filler words are those little ones like just, very, really, and quite. Removal of these words will strengthen your prose and make it seem more confident.
One way to do this is to take your manuscript and run a 'find and highlight' search. You'll be surprised, I'm sure, at how many come up. And how many you can remove.
Now, I do not advocate removal of every single one, because occasionally they are needed. Simply read each sentence where they appear and ask if they are required for the sentence to make sense. If the answer is yes, leave them be; if the answer is no, delete.