OK, it sounds like you are working at moving away from a 'chest voice' and towards the 'head voice', keeping resonance in the head and throat.
The 'chest voice' vibrates in the upper chest strongly. Place your hand on your chest and speak, or say "Ooooooooh". You'll feel the vibration with a 'chest voice', but the vibration vanishes when you find the right way to re-tension the throat muscles to 'move' that vibration into the throat or head.
I use a free app called SingScope (iOS) to check my voice pitch. The app graphs the pitch over time, and presents a good estimate of how your pitch is changing as you speak. I target the range A3-C4 for my speech. That's 220-262 Hz, which might be a bit high for some people. A pitch above G3 (196 Hz) is more likely to read as female than lower pitches, all other things being equal.
The next big items were simply practicing, and practicing more, to keep the pitch up. When talking, it is very easy to become distracted and let the pitch drop, until we've used the new range so much that it becomes automatic. After many months I am still working on this.
Setting pitch before speaking can be very helpful. This is just making a little sound that puts our speech in the right range. I sort of hum "Uh huh" with 'Uh' at A3 and 'huh' at C4 when I begin to speak, and that helps quite a bit. Again, practicing makes it easier to hit these notes.
I'm also working on pitch control. Masculine speech tends to drop the pitch at the ends of phrases or sentences. That SingScope display shows this really well. Feminine speech tends to hold pitch, or even rise slightly at the end of phrases or sentences. (This trait can make statements sound like questions; "Hi, I'm Michelle?"; "I'll have a cappuccino?")
And then there is the Holy Grail, prosody. Feminine speech has much more variation in pitch than masculine. Listening to conversations, women appear to almost sing to each other, very different than a men's conversation. I've used SingScope again to watch the changes in feminine speech and try to replicate this.
I have a bunch of practice sentences from my speech therapist that I use to work on conveying emotions along with pitch and prosody. I've also got Aesop's Fables on my book reader gadgets and phone, and I try to read one of the short stories daily, often into SingScope to make sure I'm holding up OK.