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FAFSA (Free Application for Federal Student Aid) should be filled out as soon after January 1st of your daughter's senior year as possible. The earlier you fill it out, the better chance you have at grants and subsidized loans.
To increase your daughter's chances of getting scholarships, you should encourage her to get involved in some volunteering and extra-curricular activities if she isn't already. Have her check with her guidance counselors on available scholarships, and what she could start doing to prepare for them.