SuMac Admissions

Hi I really want to get into the Stanford Math program over the summer, and next year I plan to apply. If everything goes as planned I will have a pretty solid GPA, 4.5 weighted (3.96 unweighted), will have qualified for the AIME, and not yet taken the SAT (not 100%). What else could I do to help me get in. Is it realistic to hope to qualify for USAMO if I scored very low on AIME this year. BTW next year I will be a sophomore applying for the summer before my junior year of high school. Also I am very passionate and fascinated by mathematics.