No amount of copyediting and proofing will get you
thousands of sales and critical acclaim if the work isn't ready.
A book can be error-free and still not be ready for
publication.
Or, as J.A. Konrath says, "Don't write shit."
Before releasing your work into the wild, consider
getting feedback from other writers. Your family and friends love you
and want to support you, which is great. But unless they are writers
you may not hear what you need to know to make a good book better.
You find feedback either in a local writing group or
an online group. The forums of Absolute Write are excellent and it is
free to register. To get feedback, you give feedback, and in doing
that, you can't help but improve in your craft.