There are three ways that I can think off to store your private keys safely (offline)
1) Having a hardware wallet (Trezor, Ledger, and so on). The problem: Having to trust their custom RNG, their while hardware, that there will be no surprises (see trezord.exe phoning home)
You don't have to do this. You can create your own seed offline and insert it in the machine. They'll recognise anything that's valid. Beyond that I do wonder how many other horrors will be uncovered in the years to come with hardware wallets. The spoils would be humongous.
I used to be all paper. Now I'm all hardware.
The third option sounds cool but far too much ball ache. If I'm to spend at the moment I'll get rid of one of my numerous forks, stick the proceeds in a phone wallet and go retail crazy.