hmm well practice from real life and practice a lot ofc but some personal advice? learn how to construct a head/face from its most basic forms. I somewhat learned what to do from looking at a Head/Hand drawing book by Andrew Loomis
I love seeing your process with this kinda stuff, feeling out the character. I know it's a continual process but at this rate she'll be polished to "perfection" in no time I adore the hands and pose on that bottom right sketch.