At the start, doing exercises to stretch your vocal chords and generally just practice is the most important thing. You can worry about fine detail later- a big part is training your muscle fibers to do what you want, and like any muscle, the more you use it, the stronger it gets. In this case strength won’t lead to power, but rather, control.
Pitch is the last thing to work on. Resonance is the most important aspect (if your goal is to pass). Intonation is very important as well, and there are certain ways of speaking that are associated with cis female voices, like upward inflection at the end of a sentence.
It takes time- with a good clinician in a well supported program, someone who is out and using their new voice, it may take as little as 6 months. Doing it alone via the internet, it will likely take longer (especially if you’re not out - practice is key!) so don’t get discouraged. Just practice, practice, practice!
The shower and the car (if you have one) are generally safe places to practice, and since we travel and bath everyday (ideally), it can be a good way to work in consistent practice.