Points by position
Instead of adding scores, give points for finishing places — for example 100 for a win, then down the field. One bad week costs a few places, not the season.
Dropped weeks
Letting everyone discard their worst one or two results forgives a missed week or a disaster, without rewarding anyone for not turning up.
Multipliers
Doubling the points for a final or a 'major' week gives the season a climax and keeps the people in fourth place interested.
Ties
Decide in advance. Sharing the points for the tied places is the fairest and needs no countback.