Many things have to come together in order for you to really take advantage of your mix voice. One of them is really balancing your chest and head voice. Learn more about what I mean in this video.
Sometimes we as singers just need to know what it feels like to step into a new sound. Speaking high notes can really help in that way, as it helps us not over push or hold back. Watch this video for more info on how you can do just that, and get a solid feel for just how easy singing high notes can feel!