Hi fairmaid. I've never been a good yodeler but I'll throw a couple of things at you that may help. The key that you try to break your voice in is absolutely crucial. If I sing Jimmie Rodgers' "Blue Yodel" in C,C#, or Eb or E, it doesn't work at all. ONLY in the key of D will the break be clear and on pitch. The yodel starts on the fifth of the scale and ends on the third of the next higher scale. If you're confused, maybe someone can explain it better. Good luck.
rick