So, most of my main protagonists are female, and the usual him/her doesn't work when dealing with multiple females (or males, for that matter.) So, how would I make dialogue flow without mentioning their name every sentence?
If you feel it is clear enough who is speaking, you can skip the attribution. For example, if two people are speaking, the reader would assume that they're taking turns, so you don't need to attribute every line to the person who said it. When a character addresses another by name, it also helps orient the reader, without adding "Bob said" in the end.
But mentioning names all the time doesn't necessary break the flow of the dialogue. For example, from the Lord of the Rings (lots and lots of interactions between same-sex characters there):
‘The stroke on the left might be a G-rune with thin branches,’ said Strider. ‘It might be a sign left by Gandalf, though one cannot be sure. The scratches are fine, and they certainly look fresh. But the marks might mean something quite different, and have nothing to do with us. Rangers use runes, and they come here sometimes.’
‘What could they mean, even if Gandalf made them?’ asked Merry.
‘I should say,’ answered Strider, ‘that they stood for G3, and were a sign that Gandalf was here on October the third: that is three days ago now. It would also show that he was in a hurry and danger was at hand, so that he had no time or did not dare to write anything longer or plainer. If that is so, we must be wary.’
‘I wish we could feel sure that he made the marks, whatever they may mean,’ said Frodo. ‘It would be a great comfort to know that he was on the way, in front of us or behind us.’
‘Perhaps,’ said Strider. ‘For myself, I believe that he was here, and was in danger. There have been scorching flames here; and now the light that we saw three nights ago in the eastern sky comes back to my mind. I guess that he was attacked on this hill-top, but with what result I cannot tell. He is here no longer, and we must now look after ourselves and make our own way to Rivendell, as best we can.’
‘How far is Rivendell?’ asked Merry, gazing round wearily. The world looked wild and wide from Weathertop.
(J.R.R Tolkien, Lord of the Rings, Book I, chapter 11 - A Knife in the Dark; my emphasis)
Other times, you can use "he said" or "she said" - context can make it clear who you're referring to, even if there's more than one "he" or "she" present in the scene. For example:
Éomer stepped back and a look of awe was in his face. He cast down his proud eyes. ‘These are indeed strange days,’ he muttered. ‘Dreams and legends spring to life out of the grass.
‘Tell me, lord,’ he said, ‘what brings you here? And what was the meaning of the dark words? Long has Boromir son of Denethor been gone seeking an answer, and the horse that we lent him came back riderless. What doom do you bring out of the North?’
(J.R.R Tolkien, Lord of the Rings, Book III, chapter 2 - The Riders of Rohan; my emphasis)
Here, since Éomer was the subject of the first paragraph, the reader understands that "he" in the next paragraph refers to him.
That scene continues:
‘The doom of choice,’ said Aragorn. ‘You may say this to Théoden son of Thengel: open war lies before him, with Sauron or against him. None may live now as they have lived, and few shall keep what they call their own. But of these great matters we will speak later. If chance allows, I will come myself to the king. Now I am in great need, and I ask for help, or at least for tidings. You heard that we are pursuing an orc-host that carried off our friends. What can you tell us?’
‘That you need not pursue them further,’ said Éomer. ‘The Orcs are destroyed.’
‘And our friends?’
‘We found none but Orcs.’
The last two lines are not attributed to any character at all, but it is not hard to follow who is saying what. The pattern "Aragorn-Éomer" has been established, so we can assume it continues, and although Gimli and Legolas are both present in the scene, we understand that they are not interrupting (until they do, a few lines later).