What gets a item into the best seller category?

may seem an obvious question, but…

… selling thousands of a single track, what is the process, assuming the track is top notch next to a ‘95% hit track’.
What is the process: marketing? an already successful portfolio? being uploaded at the right time?

I’ve heard many very good tracks that have only sold a few, but seem just as good as the best… so

any thoughts please?

Very simple answer for you: A track that is being found, that is also good enough.

All you mentioned above matters: External marketing, internal marketing (being featured), uploaded at the right time, part of an already successful portfolio with many views, good SEO.

Do most people here market on youtube?

Looking at the top sellers this month, if you don’t have ‘Upbeat’ or ‘Inspire’ in the title you can forget it!

Yes it does seem the way to go if you want to aim for good sales.