Everyone of us want our book published yesterday. It can't be done. We all need to slow down and do things correctly. One editor with a large publishing house told me, "Have you book in pristine shape, then send it to me." How many times are we in a hurry to get that book to the publisher? We forget the basic rules for any author. Here are a few.
Have a critique partner, or critique group. If you are writing a fiction, I recommend it as one of the most important things you can do. Find someone who has your interest, knows something about writing, and is willing to put the time in helping you publish your book. You will be helping that person by critiquing their book in exchange. Even non-fiction needs to go by these rules.
When you are sure you have your book in good shape, take the next step and invest in a paid edit by a professional. There are so many out there, and some charge hefty prices. Find one you can afford and work with. To accomplish anything, you have to invest. As my mama said, "Nothing in life is free." A paid editor will find those mistakes you overlooked.
One thing I encourage authors I am publishing with is to invest in AutoCrit. I highly recommend it. It is time consuming but it will help your writing. If you only purchase the $47 a year package, it's worth it. It will show you what words you use that don't need to be there. I overuse "that" and "it". AutoCrit will show you how many to take them out, and that's a big help to me. I don't work for the company, this is just my experience.
Realize when your book goes to the publisher, it takes time for publication. If your manuscript is in good shape, it can be handled quicker. Your publisher knows how long it will take to get a book in print and in ebook. Remember you are not the only fish in the pond. Even a small company, like mine, has other things in the mill. It may be working on their own book or critiquing their partner's book, but they have other things to do.
Work hand in hand with the publisher. Try not to cause any problems. It's not easy for both of you and you are both anxious to see your baby see the light of day. Be patient. It will happen, but it won't be yesterday.