I know, you were hoping for a better answer. Sorry about that. The fundamental problem that prevents completely eliminating spam is that anyone can send email to anyone. Spammers can get your email address in a variety of ways. They can guess it, they can get it from your website, you gave it to them in a web form, they purchased it from hacked accounts, you unsubscribed or replied to a phishing email, someone else who legitimately had your email address inadvertently supplied it, etc.
Sure, you can reduce the volume of spam by utilizing filters and blockers in your email server and/or your email client or by purchasing a spam filtering product, but you will never completely eliminate spam. And of course, if you are too aggressive in attempting to filter spam, you might miss a legitimate email.
So, my best advice is to accept the inevitability of receiving spam, judiciously use the spam reduction facilities in your email system, keep up with deleting spam, and empty your email Junk and Trash folders frequently.