It depends. I personally dislike using raw midi files and turning them into abc files. I have a music background so I personally just work off pre-existing sheet music that I own. Or I will use a 1-page preview from musicnotes.com to give me a jumpstart, and then figure the rest out by ear (usually listening to the song in question on youtube if I don't have it myself). It is a very long and complicated process but it feels a lot more rewarding to me when it's finally finished.
I use Anvil Studio to create my songs (it saves as a midi file) and then use Maestro to convert to abc. I use the ABC Player for quick playback. I'm hoping to get someone to show me how to use Firefern -- it is rather confusing to me -- because I have a song that I need to fade-out, but mostly I use the other 3 programs.
R5 100 GRD Marevayave - Leader of Riddermarked For Death
R8 100 MNS Fayah/100 LM Siennah/100 HNT Dinenol/100 RK Dhurik
100 CHN Alachas/85 CPT Dinfaerien/60 BUR Dhax/35 WDN Godoric
R9 100 MNS Fayeh (alt Wilya) - Lonely Mountain Band @ Landroval