If you want really good fried potatoes, bake your potatoes today. Let them lay out on the COUNTER overnight. Do not refrigerate them (I don't know what it would do to them...maybe ruin them, maybe nothing?) Tomorrow, cut them into quarters, bite size chunks or fries and deep fry in HOT oil until brown. Salt.
I learned this trick at a steak house I worked at. They did this with "left over" baked potatoes each day. Actually, they baked extra potatoes so they would have left overs