Madison, the best exercise I have came from a pro (and college prof). Start somewhere between a second line G and a third space C. Play each note softly and without as much pressure as possible. Set a timer on your phone (or something) for 30 seconds for each note. Play all the way down the scale (by half steps) as far as you can...or until you are totally bored. Each note, good sound, soft...30 seconds. Really worked for me for embouchure building. Hope this helps!