Turn into a monster and use special ability on doom (frog). He might turn into a frog and you can escape (not item keeper).
to level up magic you have to use that item alot like say i wanted to get thunder to the next level and make it stronger u have to use thunder books and use 10 to get lv 2 thunder
to get :
ramuh feather:go to the restaurant above chubby chocobos store, talk to the malboro(repeatedly) until he asks you to hit him with thunder books say yes and hit him with thunder til he turns into ramuh
slyph feather:go to the beach til you find a chest open it and leave the beach go back and do this repeatedly till slyph appears
other feathers :
get claws that have attributes (dwarf,silence,flame,ect.) and get them to +1 at least then use them till they break by a 99.9%chance you will get a feather related to the claw attribute (dwarf is dwarf chaos gets confusion but no healing :<
first of all its quite easy first stock up on leveledup saddles (wood,iorn,mythril 4 no waste )make sure u make a total of 10 or more like 10 +1 woods ect. then get a lamia ecsence then mix it with any 2 saddels make sure theyr leveled up and keep mixing until its at least +10 break it and ha ha ha here coms bahamut buhaaaa