Do you use a voice recorder to check on yourself? If you do that, then try talking in different "head voices" and find one that would suit your speech, once you find the "head voice" of choice try continuing to simulate how you accomplish that throughout the day without straining yourself. Go with that for short timed intervals until it becomes more natural to talk like that.
I've tried testing a voice recorder, and i sound like the lower female range to be honest. Luckily all my life over the phone I've been "mis gendered" as female for as long as I can remember. So I just talk as I do with that, trying every once in a while to check if I can gain a slightly higher pitch.

Kate <3