if you use a free email provider like Gmail or Outlook, then ensure 2-factor authentication is enabled - this is where you sign in to your email account and get a text message or access code on your mobile phone to complete the authorisation
don't open spam emails
turn off images in your email, and only re-enable for senders you know are legitimate
The ICO blog has a great post on ransomware, the despicable act of holding a business to ransom by preventing access to the files on their computer. These things always begin with a virus, usually through a spam email. Once infected your computer is locked down and access to your important files restricted. The pirates then issue a demand for payment to permit access again... or they will delete them. This is when having external backups comes in handy! Of course, the best defense is to avoid catching the virus in the first place.
I can confirm they've changed their business names to include keywords
The lengths some businesses will go to perform well in Google Business Search! If it's not a spammy business names or fake business listings, it's review spam (self-reviews & competitor shaming). Read more about Local SEO Spam Tactics and what you can do to prevent the issue from escalating.
If you use Google's Gmail then you can do the same type of thing using this nifty "+" sign technique. Simply add something extra to your email username to define which service or special offer you're signing up for to find out which websites are selling your email address to marketers. For example, if your normal email address is firstname.lastname@example.org and you're signing up for a competition with Little Goliath Ltd you would provide your email address as something like email@example.com. Thereafter, any emails arriving in your inbox to that very specific email address indicates who sold your email address to who.
We all hate spam, right? Well, so does Canada. They've recently passed a new law that will see them issue financial penalties of up to $1 million for individuals and $10 million to businesses that send email to people without their consent. And this law doesn't just apply to Canadians, it affects everyone. Here's what you need to know about the new Canadian anti-spam law. And here's the official documentation on the new law.