This is good, but I use my computer a lot. I have a lot of sticky notes all over my desk at work, but I then put them on the computer at home later.
I keep a running log of rhymes and lines that I think up on the spur of the moment. I also record guitar licks I come up with. I collect common things people say or something I overheard that I think I might use. Then when I get inspired, I use my log to build on my lyrics or if I'm stuck for a line, I go to log.
I like using the computer because it's so easy to switch things around or change completely while keep the orginal thought.
I would be careful using other songs to create your own. You maybe violating some copyright laws. It probably won't be a problem, unless your song makes it big time. Then everyone and his brother will be after a piece of the action.
I had a problem years ago when my song resembled the song "Snow Bird". I wasn't fined or anything, but it cost a lot of moola for attorneys and time away from work. I didn't even use the song, it just had similiaries.
Just some friendly advice.