There are a few different things you can do to lessen your spam, and to be safe from phishing email:
If you want people to contact you over your website, use a form rather than posting your email address on the web. Having your email address on the web is any easy way for a spammer to harvest your address.
Never reply to a spam message, even when they ask you to reply to "remove" you from their list. If you feel that this message was sent from a valid source, look them up on the web and contact them directly to remove yourself from that list.
Opt out of anything you aren't totally sure of when you buy something online and have to provide an email address.
Do not click on links within an email. It is always safer to type the company name into the web browser to access the company web page.
Always keep your security software and operating system patches up to date.
