Use Two Different E-mail Addresses
You might already know about Gmail aliases, which is to say, using periods or plus symbols to extend your standard Gmail address so you can filter for spam.
What you might not know is that you can use @google-mail.com as well as @gmail.com. In other words, if you normally use example.address@gmail.com for your e-mail, then you can also use example.address@google-mail.com , and the message will still reach you. You could use @google-mail.com when signing up to newsletters, for example, and create a filter rule within Gmail to sort any messages sent to that address into a spam folder.
The @google-mail.com address came about because of trademark issues in Europe, where Gmail was already being used by rival services.