My reflex initial actions are to block unwanted stuff on Web pages (which is good for speed and security also) with NoScript and your browser's anti-tracking su

My reflex initial actions are to block unwanted stuff on Web pages (which is good for speed and security also) with NoScript and your browser's anti-tracking support at least, and have your mail client ask you before downloading large items (~100kB, which are often malicious also). And turn off any applications that may be chattering in the background without telling you.