H is almost always mute in Spanish.
-a hard G before A, O, and U. (gato, amigo, gustar)
And with the consonnant (gr, gl...)
-The soft "g" (looks like the jota "j"): before E or I: (gente, eligir...)
In some parts of Latin America, the soft G and jota have a very guttural sound, which comes from the back of the throat.
In Central America and the Caribbean, they have a very soft sound (closer to an English H), almost like you're breathing through the letter when you say it.