What advice would you give a beginner writer?
My advice to a beginner would be to (a) join your local writers centre and learn about what you're getting into with publishing and (b) engage a professional editor. You could learn a lot from a publishing consultant, an editor or a book marketing strategist, but it does come at a cost.
Think about your own situation, time availability, budget and whether you think traditional or self-publishing is the best option for you. How much do you want to learn yourself from a club like a writers' centre (low cost)? Or would you prefer to get personal professional information fast (high cost)?
In any case, every writer needs an editor at some stage for their book to be any good. The question is when is the right time to engage one. Most authors need to go through a process of drafting, sharing their drafts, workshopping with other writers, and self-editing, before it makes sense to pay a professional editor.