Freshman, new to this

Pretty familiar with the college application process in general, but very unfamiliar with the transfer process and it’s differences. I have a few new things getting done and am matriculating this week to a T100 state school this week. What should I get started on and be ready for at different dates and focus on? Planning on GPA maxxing, but want to meet reqs as well, I have 3s on AP BC and AB, and max score on a math placement, but wondering what I should take this year that’s acceptable but not breaking reqs or expectations.

Business/financial and behavioral econ/psych/computational neuroscience