For example, sell everything for bitcoin, store it in hardware/software wallet.
Done.
Other ways are store every coin in separate software wallet dedicated for it on your PC.
I know its a bit pain in der arse, but, you don't need to worrty about wallet security then, because not official wallets can be infected/backdoored.
Some hardware wallets offer many altcoins, but altcoins are limitless so they cant support most of them even.