I am not talking about whether I can submit a paper on subject A to a journal on subject B.
My question is:
How do I know how good my paper is? I could of course just sentsend it to the best journal in the field, and see what they say, but I also don't want to embarrass myself and waste their time. If, however, it is very good and would be accepted by such a journal, it would be unwise to publish this in a lower ranked journal I would think.