Quick Pick Trick
Here is easy pick trick I do when playing jazz, but it will work for any style of music. I normally use Fender Medium picks when I play with a pick. For me they flex enough for strumming yet are is still heavy enough for single notes.
Sometimes, though, I want a little more warmth (and volume) from the pick when I am playing a melody. So I strum chords with the point (bottom) of the pick and then turn the pick a quarter turn and use one of the more rounded edges (top corners) for picking single notes. Because the pick is more rounded on those corners it doesn’t flex as much and acts more like a heavy pick. Heavy picks are louder (and more unforgiving) than medium picks, so when using the thicker corners, the melody is louder.
This will also work for switching between chords and riffs.