For back to school i usualu go by the "5" rule where you get five of each important clothing item (one for everyday of the week) so get like 5 shirts, 5 pants. When it comes to shoes 2 good pairs is helpful (one casual one sporty) and just try to see whats resonable
Usually when I go back to school shopping, I pick around 3 outfits. Basically 5 for the first week, and I can rotate the other 3 outfits on some days so it looks like I don't have only 1 set of clothing so I don't look too dirty just wearing the same clothes every week. Usually I get new clothes on Christmas too so I put those in the mix.
