This is a great, to the point, presentation by Kit Needham, an Entrepreneur-in-Residence at Carnegie Mellon University. It defines direct and indirect competition in simple terms and even given an example of a fashion brand competitive analysis.
This from the US SBA is a good place to start. Some of the resources they link are elsewhere in this guide, but I think the clear layout of the components of a competitive analysis may be very helpful.
U.S. Small Business Administration
The link bellow is helpful high-level overview of
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