I have a similar set-up with some minor differences.
First, after downloading I use Fakin' the funk to check on bitrate/spectrum of a track. Is that WAV really WAV or MP3 converted to WAV. The good tracks are then moved from the Download folder to my Music Prep folder.
I then put it through Kid3/MP3Tag and make sure the tags are cleared of DJ Pool advertisement. And the file name is <artist name> - <title>. This helps prevent me from adding duplicates to my library I forgot. Once this is done the tracks are moved to my Music folder.
Next up is importing into RB and analysing. Also start using MyTag. This feature is one of the most underrated things in RB.
Not everybody agrees to putting all your tracks in one folder.