for a room in the house usually its impossible to get good padding and still make the room look 'nice'.. but things you can do are putting in some sofas(good sound absorber), rugs/carpets, bookshelves against the walls which are full of books(again excellent sound absorption), hanging rugs on walls, heavy curtains on windows(excellent also)....
for ceiling, usually can't do much. So basically u can cover 4 or 5 of the 6 sides of a room (floor, 4 walls and ceiling) which if done properly should be good enuff.
having the wall plastered with egg shells looks really ugly.. hahaha..
When u jam, u may want to leave that glass cupboard shelves open to break up the flat surface.
but for your case, u should really try putting the speakers behind the microphone first and lowering the volume of the drums