OP, are you on Android or iPhone? The advice would be OS specific.
In general, use encryption, with a good passphrase[1]. Fully power down your phone in dangerous situations, like when crossing the border or pulled over by law enforcement. Practice data minimization. For example, turn on Signal's disappearing messages feature - do you really need to look back more than a week at your chats?
Install a VPN since you'll be using a lot of suspect wifi.
And personally, I avoid logging into anything super sensitive (ex: retirement account) unless I'm at home.
Enable encryption on your phone. Limit the apps you use. Limit permissions to apps. Even tho apps can only see their data. You can create separate users to further limit data access.
Please stop parroting this fallacy. Unless you operate the VPN server that you are connecting to, which most people won't, then you aren't doing much to improve your privacy at all. You're just redirecting all of your connectivity through some other third-party which may or may not be trustworthy, and from there, onto some other ISPs which may or may not be trustworthy.
>Please stop parroting this fallacy. Unless you operate the VPN server that you are connecting to, which most people won't, then you aren't doing much to improve your privacy at all.
This is not factually accurate.
Redirecting your connectivity can be a good thing, if the VPN has a strong privacy policy, since ISPs are pushing to be able to sell browsing histories (via DNS records).
And a VPN is great when your "ISP" is unencrypted public wifi.
You might not be able to trust your VPN provider, but if you're paying them and they're relatively reputable (located in the US or EU) they will be regulated if they violate their privacy policy. (Ex: deceptive trade practice invokes FTC's section 5 authority)
Also, we're on HN - many of us roll our own VPN with Streisand etc.
Maybe you should stop parroting kneejerk contrarianism every time you encounter common advice.
Any data on your computer, phone or online is already compromised or can be at anytime.
I don't think private data exists.
There are steps you can do to help keep data more private but nothing reliable or for sure.
If it's online or in your phone I'd assume it's not secure.