Try using a piano, starting somewhere above middle C, and focus on one note at a time. Hit the note over and over while talking monotone, then go up to the next note, continue doing it until you can't go up anyone, then work your way back down to your starting note. Then practice going up and down notes with every word, to give you the dynamic inflection that women typically have. I've helped a lot of people work on their voice, and I trained my own voice doing this... and today I can't sound male if I try.