How can journalists and activists (and regular folks) reduce their susceptibility to surveillance?

The recent news of a savvy UAE-based activist thwarting an attempt to compromise his iPhone raises the important issue of state-based surveillance actors and their private sector contractors having sophisticated and effective ways of intercepting communication and using their targets' own devices against them. One problem with modern mobile computing technology is that it's been built around expansive and convenient features, with security and privacy as an afterthought. On the same day I learned about the iPhone exploit, I happened to listen to a re-run of a 2014 Planet Money podcast in which an NPR journalist volunteered to fall victim to his unencrypted internet traffic being captured and analyzed by experts, and what they were able to learn about him, and specifically about the sources and topics of a story he was working on, was alarming. As the podcast mentions, mobile OS vendors and online services are getting a lot better at encrypting traffic and obscuring metadata, and one of the primary reasons for this was Edward Snowden's revelations about the ubiquity and sophistication of the NSA's surveillance, and by extension, the dangers of surveillance from other state agencies, black hat hackers, and legions of scammers. The Snowden revelations hit Silicon Valley right in the pocketbook, so that did impel a vast new rollout of encryption and bug fixing, but there's still a long way to go.As a way of both highlighting and trying to fix some of the inherent vulnerabilities of smartphones in particular, Ed Snowden teamed up with famed hardware hacker Bunny Huang have been working on a hardware tool, specifically, a mobile phone case, that monitors the radio signals from a device and reports to the user what's really being transmitted. They explain their project in a fascinating article at PubPub.Mobile phones provide a wide attack surface, since their multitude of apps are sharing data with the network at all times, and even if the core data is encrypted, a lot can be gleaned from metadata and snippets of unencrypted data that leak through. Journalists and activists generally know this, and often use Airplane Mode when they're worried their location may be tracked. Problem is, when agencies are using spearphishing attacks to remotely jailbreak iPhones and install tracking software, and there are even fears that OS vendors themselves might be cooperating with authorities, Snowden and Huang set out to allow users to monitor their devices in a way that doesn't implicitly trust the device's user interface, which may be hiding the fact that it's transmitting data when it says it's not. The article goes into great detail about the options they considered, and the specific design they've worked down to, and it looks terrific.