Questions about preventing hair loss or slowing its progression

I thought it was just that my hair was thin and I had less hair, but my hair keeps falling out.

It's not as serious as it is for men, but the M-shaped hair loss pattern is evident enough to make it difficult to say that my forehead is wide.

I need to take some action before it gets worse, but I can't figure out where to start.

Apart from using shampoos that are said to be good for hair loss, I haven't done anything special yet.

Please advise if anyone knows how to prevent hair loss or slow down its progression.