I used Media Center Master to download backgrounds and rename files nicely for Plex but after rebuilding my HTPC, something is wrong with the latest iteration of the program and it simply doesn’t work that well.
Is there something else I should consider?
Not sure if Plex uses the info created by MCM but it’s a neat tool to rename files properly.
Posters and backgrounds don’t need to be downloaded in preparation; that is Plex’s job (unless you put great importance into defining which particular artwork is being used).
Apart from that, sticking to Plex’s guide lines for organizing and naming your media is key to success: Category : Your Media | Plex Support
Particularly
adding the release year in round parentheses after the official title
giving each movie its own, individual subfolder (is a snap with software like the above mentioned Filebot)
Avoiding additional folder levels when working with TV shows (series)
looking up the titles in question at IMDb.com, TheMovieDB.org, and TheTVDB.com to clarify their official titles, original release year, and the classification as either movie or tv show