Apply the reviewers' comments, within reason -- you are unlikely to have the same reviewers next cycle. Your proposal in general should be improved commensurate with your greater experience as a second year student.
For BI, try finding more concrete outreach, and then performing it. This could mean mentoring students 1:1, talking about science on a public platform (blog, lectures in elementary/middle/high schools), or finding ways that any disadvantage from your own background has influenced your career and will contribute to your research being able to enhance the experiences of other disadvantaged people. You can't overdo BI in my experience. To the degree that BI can be integrated into both your research proposal and your personal statement, that's optimal.