Best way to insulate a cement basement?

Answer 1

there is big rolled fiberglass insulation that you can wrap around the walls and have plastic put over it to protect and have it stapled or nailed with cement nails to keep it in place. Also, insulate the cieling, and get that foam or whatever it's called that expands and fills in cracks and holes and dries hard like hard plastic.

Answer 2

If you want to put paneling or sheetrock on the walls after insulation you will need to put furring strips vertically on the wall. If the basement stays dry you could put 2x2 or 4x4 at 24" on center. If the walls get wet in the winter use metal studs or furring channels. Use 1" or 1 1/2" styrofoam sheets cut to fit. These can be glued to the concrete with construction adhesive.

If you are not going to cover styrofoam do not use it. It produces toxic gas in the event of a fire and codes do not allow for styrofoam exposed on a wall.