Personally, I find that if I get frustrated of getting my butt beat on H/H, I just simply go back to playing M/M for a game or two before trying again. It's much simpler than cheating and just as rewarding.
Of course, I have heard others say here that if the game "cheats" for the AI on H or VH, then they use cheats, too.
"He said, 'Why should I tarry?' And smiled with tranquil eye; 'In destinies sad or merry, True men can but try.'" Sir Gawain and the Green Knight (Lines 562-565)