Regarding Kegg

This isn't exactly a technical question(I believe so), but I'd like to ask about kegg, which I'm new with if anyone has previously worked with it. For non annotated proteins, like not available at ncbi or uniprot, so they are only in raw fasta format, is my best option just doing a blast for my proteins and going for the closest homolog if the same ones can't be found in the database? Is there maybe any other pre-processing tool I should be aware of, regarding protein annotation in any way?