Green day style writing

i dont own insomniac, but if i am in a green day type mood one day, and wanna do a green day type song here's how i've always gone about writing the song...

Guitar part first.... A very simple progression that sounds good together, generaly made up of no more than 5 chord changes, with a measure per chord

Bass part second... I lay the guitar part to tape, and then start messing around with the bass. I normaly start off with just playing root's, that way i get a feel for the song, and how much room i actualy have in there. Then i start adding little walk downs to the next note before the guitar gets there, but meet on the new note at the same time, or little pull off thingys inbetween. Its really a basic way to write a song, and is fairly easy to do once you get it down. Rember though, there is such a thing as too much movement, you dont want to get in the way heavily of the vocals. Take advantage of the breaks in the vocals. Often you'll find a window to do a simple bass fill that might be super easy, but sounds pretty cool on tape.