A Dictionary and a Thesaurus

When we are writing in English, we need to be students of the language.  And The words we use in our everyday speech do not compare to the plethora of words available to a writer.  Dr. Seuss wrote a book using just fifty different words (Green Eggs and Ham), so obviously we can write using very few - but how many words are there?
research into the subject found all kinds of data, but basically I think we can agree that English consists of hundreds of thousands of words (maybe 1 million) but the spoken language used every day by most people consists of about 40,000 words.  So to be a fluent speaker you do not need to know hundreds of thousands of words.  That's good news - but what about writers?
Walk.  I type in that single verb on my computer and right-click for synonyms and get 8 excellent suggestions.  If I'm not happy with those 8, I can click on the Thesaurus for even more.  Now when I write a romance fiction I will not be happy to have my character walk home at night, but she will saunter, stroll, amble, or march home; depending on her mood of course.  And in my science fiction novel my male lead will stride, pace, or hike to the next mission.  Adding some variety to our verbs can really help the reader to ascertain mood without having to tell them that our character was in that mood.  I am firmly against spoon-feeding the reader.
Maybe this is a free book, posted online for readers to find free fiction.  There is a lot of competition and many of them are spoon-feeding their readers.  Be different!  They want to read a novel online, they will appreciate the effort you made to use a dictionary or a thesaurus.  Fiction is a chance to escape reality, but does not have to be mindless.  The man marched to the door and flung it open, he expected to find his wife there with his brother and was ready for anything...except the truth!  Isn't the verb "march" better than "walk" here?  The girl stepped out of the bar and toddled to her car, not a care in the world.  Don't use the word walk in your romance novel, it just doesn't belong.
Sometimes I worry that writers of fiction are concerned about breaking their "groove" and don't want to interrupt a thought - that is valid.  A dictionary and a thesaurus can be used when you are proof-reading the passage later.  If you are typing away and don't want to stop - don't!  Even if you can't think of the word you want, just type in the idea in [brackets] and keep writing.  We want you to put words on paper, we want you to be a writer and contribute to Literature in general, so don't stop writing to look anything up if you don't absolutely have to.  But do not neglect the importance of going back and re-reading this work with the intention of making it better.  Change adjectives and verbs - that's where a dictionary and a thesaurus will really come in handy.
Look at your favourite novels and see what words the author used, you will see that he has done a great job of indicating mood with his verbs and adjectives.  Popular books have teams of people researching these types of details, and if you are planning to post your book online for people to read free, you may be alone.  Online reading can get you followers and constructive criticism.