You haven't provided enough detail to be able to help you much.
A general response:
perform a Find for the records you want to be in your report. Sort those records as needed to get the order and grouping needed for your totals and subtotals.
Is there a way to retrieve certain records without performing a find?
For instance say I have an inventory of clothing, shoes and accessories but I just want a sub summary report only for shoes...how can I eliminate the clothing and accessories from the report?
That question makes no sense. Why would you not perform a find to find only records for Shoes? That's the simplest, most direct way to set up your summary report.
There are other ways, but as they produce exactly the same result and via a more complicated process, I don't see why you wouldn't just perform a find.