Organize a party around a science or building theme. Have the girls prepare a collage of famous women scientists and mathematicians. Have the girls guess who the various people are, and what they contributed to their fields. Cultivate your daughter's interest in how things work by having her tinker, take things apart, and put things together. Keep expectations high.
Children are natural scientists because of their inquisitiveness.
Encourage her to learn how to repair the loose chain on the bicycle, program the VCR, take apart a broken appliance, fix the toaster, change a tire. Work with her as she does these things. Encourage girls to take high-level math and science courses. Math is the gateway to computer careers. Hire a tutor if necessary.