You need to do a number of things:

☆ Learn how to use the light-meter in the camera to choose a good exposure balancing the shutter speed and lens aperture.

☆ As you learn how to use the light-meter, practice over and over so that eventually you can do this intuitively.

☆ There are many other fundamentals of photography which you need to learn so that you can spend your time creating amazing images, not fiddling with your camera.