There are multiple sounds using the letter A. The difference is where the sound is created within the mouth. There are sharp sounds, regular sounds, and hollow sounds. In order to pronounce the various sounds of A correctly, we should look at the differences and practice them separately.
First, the sound of A that comes from the front of the mouth are the opposite of hollow sounds so I will call them sharp sounds (although the A sound is not really sharp).
Here are some words that come from the front of the mouth.