I often browse through music from old obscure SNES games or midi files looking for background music for my little games. That's my usual approach. Maybe I'll find something good I haven't used yet.

Places to find SNES music

SNESmusic.org

Download the SPC files

Zophar's Domain

I usually make a list of moods for the scenes in the game. Then I look for music that conveys those moods.

…Then I drag shortcuts of the various songs, label them with their moods, and place them into a "possibilities" folder. Then I compare them to each other to figure out which ones work best and sound best together.

I pick the best ones out of the possibilities and copy their shortcuts out of that folder. Then a open the original songs and export them to WAV files. If it's a midi song I usually replace the instruments with a better soundfont like Musica_Theoria_v2

I use Winamp

Winamp Program

... along with these plugins

Winamp Retro Plugins

Incidentally, Addams Family Values on the SNES has WAY better music than you would expect considering how primitive the game looks. It's impressively well composed and very moody.

Dragon Quest VI from the SNES seems to have a lot of thematically useful music. It even has some leit motif which gives many songs similar melodies, making them seem to belong together. Could be useful. RPG's tend to have a useful variety of musical themes.

I cut the songs into clean loops and encode them as mp3's for my RPG Maker. I use a program called mp3loop to resample the loop portions very slightly and encode the mp3's in a way that allows them to loop seamlessly without the audible gap you'd normally get.