Merry Christmas first of all! I did consider making a "list" on my blog of how I sell my models and what methods I use to determine what to make (if they hadn't been requested separately). I may just do that after the Christmas madness is over.
I spend around an hour sorting a model out after I have finished it as I upload to several platforms and then I like to "advertise" said model on many more. Facebook, Twitter, Blog, website, Discord, Reddit groups, Steam groups and a few other forums etc. This has been quite successful. It all boils down to how much time and effort you put into it just like anything else.
I haven't bothered doing the freelance thing here because I usually have projects to complete already and I really don't want to get stuck having to make furniture and things I don't particularly enjoy modelling, but if you're just here for the money then may I suggest you give that a go?