A common mistake is relying too much on pitch. You need to tighten your throat to change the resonance and then veeery slightly increase the pitch to your desired level. I found a little hack to get my throat ready was to sing the "where are you? and I'm so sorry" line from Blink 182's song I Miss You, or really just any pop-punk voice. Sing it and then try to hold your throat muscles in that spot and then you just have to pitch your voice up a bit but don't overdo it on the pitch, cis women are not actually as high pitched as you might think, it's mostly the throat (and vocal resonance) that's doing most of the work there.