Another cool thing to do when writing a chord progression is to emphasize different modes in the same key for different parts of the song.

As an example you could start your verse on one of the major modes then switch to one of the minor modes for the chorus etc.

Your notes to improvise with will remain the same throughout the song (take them from the parent scale) but you will see how the song will lean on different sounds in different parts of the song.

/Dave