One thing beginners often forget is the light;l specifically, where is it coming from.
So tip: always ask yourself that in every picture. Where is the light coming from.
In the picture above, I asked my model to turn towards the light (which was window light on the north side of the room; i.e. soft reflected light). If I had not done that, the back of her head would be lit. In portraits, I think carefully about where the light should be coming from, and usually the answer is “from 45 degrees above, in front of the subject, perhaps left or right slightly”.
And you can do the same. As long as you ask the question!