If you are really concerned about using password managers, or don't want to for other reasons then although it seems to go against all the advice given by the infosec community, I'd say use a different password for every site, but write them down on a piece of paper and keep that paper safe somewhere.
For some private individuals this is the sensible approach...
I'm a paranoid infosec professional too, but we need to understand the actual risk here. If you keep a list of passwords on a piece of paper in your house for example, the risk is that you are burgled (which, depending on your location may be very low) and that the burglar knows what they have found and then go on to exploit that before you have a chance to change your passwords.
If you use the same password everywhere because you can't remember different ones and you don't want to use a password manager then the risk - as others have pointed out - is that someone will compromise one of those passwords online using remote technical exploits and then attempts to reuse it on many more sites.
The risk of password compromise online is, usually, considerably higher than a burglar or other physically present attacker using your piece of paper with passwords written down.
To be extra safe I'd consider locking your piece of paper up safely or at least not keeping it somewhere on display!
If you can use two factor authentication along with this approach - such as Google Authenticator on your mobile phone to reduce the risk further then all the better. Most large sites now offer this option and you should use I whichever password approach you take.
So I know that this may get down votes from some people but I strongly believe that this is a matter of understanding and dealing with the actual risk. I advise my father to do this because otherwise I know he will use the same simple password everywhere and he is not technically experienced enough to use a password manager. For clients and IT trained people, and for an organisation's employees where you can enforce policy, a password manager and 2fa is absolutely required.