How to avoid being spied on? Become someone else.
It always comes down to this solution in the end. The more resourceful and experienced the opponent is, the more you need to put dedication into it. It is easier to do if you are still "flying under the radar" undetected by your opponent.
How to become someone else? That depends who your opponent is. If it's a stalker, you might just need to change social apps accounts (cutting some social links in the process) and move from where you live. If your opponent is a national intelligence agency that is already spying on you... You might have ditch your computers, phone, friends, home, job, etc. and try to live without identification papers (or SSN if you are in the US) and associated services.
If you are tech savy, you can build from scratch one online persona per activity. Each persona should be disconnected from the others. The best is to use one internet connection and computer for each. If that not possible, the next best option is to use a new computer with the Qubes OS distribution (or different Tails configurations), configured with one Tor router per persona. Never set up Tor hidden services, because they are not hidden from intelligence agencies resources. Do not use phones for those personas. Never connect those personas with your physical activities. You would still be spied on personally, but your personas may have a chance to avoid being spied on. However, be warned that Tor is not fully reliable against national intelligence agencies. Be also warned that every connection exiting the Tor network is likely to be heavily spied on by intelligence agencies, so the personas will attract attention on themselves. Distrust VPN services.
If your main identity must be hidden from national intelligence agencies, being tech savvy will not help much. You just have to look at what happened to Snowden or Kim Dotcom, who were tech savvy. The best option is to stay safe, stay legal.
As a side note: Encryption is just a tool. It might prevent intelligence agencies to read the content, depending on how properly it is done, but alone it will not prevent them from knowing who is talking to who, and they might even guess the kind of content of the communications based on the context alone. In your question you focus on protecting your data (stored at home or in transit), but what you really need is to protect your identity ; protecting your data is just one of the steps towards that goal.