Whether you outline in detail or just make some basic notes on characters and conflict (HtTS Lesson 8), this is your chance to figure out if the choices you’ve made are leading you in the right direction.
I had this issue with the protagonist of Book 1 of this new series. I chose a profession for him based on what I thought would be cool and useful further down the line, but when I came to work out how he’d acquired these skills, I realised there was a modern-day parallel that would take me into politically sensitive territory. In another book or in the hands of another writer that might be fine – but it was the wrong direction for this series.
So, I sat down and worked out which parts of his backstory I had to throw out and which I could keep, then took his life in a different direction that would nonetheless bring him to the place I’d envisaged the book beginning. As a bonus, it’s changed his personality in ways that I think will fit far better with the plot I have in mind, as well as totally solving the naming issue I was having.
In summary: don’t be afraid to interrogate your ideas. Better to throw out five hundred words of outline (as I did) than twenty five thousand words of first draft!