I'm having trouble making grilled cheese, what am I doing wrong?
Preheat your pan on low to low-medium.  Build your sandwich.  Butter the bread or the pan.  It doesn't matter.  Place the sandwich in the pan.  Keep the heat low, to low-medium.  Wait.  Check the underside, looking for a golden brown.  You want the heat low, because you want the cheese to begin melting without burning the bread. Be patient.  When you see evidence of the cheese softening and a golden toasting, flip your sandwich.  Again, be patient.  You may have to adjust heat until you find the sweet spot for your stove, but keep it low, and complete the task by looking for melted cheese and golden toast.