What's the voters liked in the past, they'll probably keep on liking. For instance, a general rule of thumb is that whichever movie got the most nominations is going to win best picture, and only movies that win best director nominations will have a shot at best picture. These are the two most important rules in choosing a best picture winner. They are fresher in voters' minds. Just like peas and carrots, Jenny.
Actors get brownie points for gimmicky and flashy roles.
Playing someone that is handicapped, retarded, a prostitute, a gimp, a drag queen, a deaf-mute amputee or an Eskimo is often rewarded at Oscar time, especially in the supporting categories. It doesn't get much flashier than that. The movies that impress the voters most in these categories take place in the past, preferably in a foreign country. Those voters ain't subtle. Most of them are old, blind and incontinent.