I know nothing.

I know a little.

I know everything.

I know only a little more.

I know nothing. 

When I was completing my first novel this is how I felt. I cannot tell you how many times I cycled through these five stages (or perhaps four when I look at them).  The stages were applied to writing drafts, revisions, reading through a beta reader's notes or listening to voiced critiques, more revisions, creating a query, synopsis, biography, table of contents, creating a book cover, learning the stages of self publishing, learning the stages of traditional publishing, learning to build a marketing platform (including social media and building a website from scratch).

The lines above are the part of a single lesson that repeats itself.  Do the best you can with what you have available to you and remember that with each step into the unknown, you are a little closer to standing on what you do know.