Same camp as Kompressor, got it downloaded but have yet to watch it.
I've been following all the leaks from day one though. The scariest stuff like remote controlling your phone can only be done if they target you specifically and hack your device, and depending on how secure your phone is they might even need physical access to do that, so I wouldn't worry to much about it.
The main concern for general population is TEMPORA which captures the internet activity of the entire country and stores contents of communications for three days and metadata for thirty days. This information is used to profile everyone and determine how likely they are to commit crimes.
See here for info on how TEMPORA is used to profile everyone using search history, social media, and even the radio stations you listen to:
As that video points out, this doesn't even work to make us safer. ISIS built itself up just fine during all this surveillance and even the FBI admitted it hasn't helped them crack major terrorism cases.
The whole thing is very Kafkaesque. Specifically his story The Trial where someone is being tried for a crime by a secret court where he has no idea what crime he's committed or what their process is to determine his guilt. GCHQ is essentially doing this to the entire country, or almost the entire Western world if you factor in the information sharing within the Five Eyes.
Use a VPN and pay for it via bitcoin is the best option. Strictly speaking even that cannot evade mass surveillance completely as you should assume the data centres the VPN uses are also being monitored. But since those have the traffic from many different users coming in at once and a good VPN will not retain connection and traffic logs it certainly makes it more difficult for anyone to track your usage specifically. It also depends on the country the server is located in - a US server can easily be tapped by the NSA while a server in Switzerland or Panama is a lot less likely to be collecting bulk data. There are also countries like Russia and Hong Kong which are likely to be monitoring but are very unlikely to share information with GCHQ and likely to disregard random browsing history of non-citizens.
It's also good practice to use secure communication services, because for example if you talk to someone through Facebook a VPN won't make that any more secure because they care little for privacy and are probably happy to share information with GCHQ and others (how else would TEMPORA store the contents of your messages?). If you want secure communications use encrypted email like Tutanota and ProtonMail. On your phone use TextSecure (Android) or Signal (iOS) both compatible with each other and come from Open Whisper Systems which Snowden has highly recommended.
And don't use WhatsApp either. Their security is practically non-existent. Last I checked, WhatsApp actually encrypts all communications with the same key which is stored in plaintext in the app, which means it might as well have no encryption at all. Even Saudi Arabia, who back in the day complained that they wanted a backdoor into BBM because it was too secure, previously complained what WhatsApp wasn't secure enough.
Who the fuck is Psychoactive Substances Bill and why is he taking all my drugs?