O Come, O Come, Emmanuel
Sugarland
or you could say it for something good for others . . .
maybe peace in certain global locales?
and you can start the novena any day you want but the period you suggest is traditional.
I've found that Novenas are a good way to pray. Nine days of focus on an issue or problem, the health of someone perhaps, and it's only a few minutes each day but . . . wow.