On Debian, you need to have secure boot disabled in order to hibernate. I'm guessing it works similarly on mint

Gather a lot of mint, put it in your cave in a pile, and lay down on it before going to sleep for the winter.

Someone can correct me if I'm wrong (I'm only half remembering), but don't you also need as much swap as you do RAM to hibernate?

You can't. Mint is a natural stimulant.

Haven't used Mint in a while, but I think it's mostly a function of the kernel. IIRC, there's a nice GUI for selecting what kernel you want on Mint. Would probably only make a difference if you have new hardware and need a newer kernel.

Since you have no details, i'll just send you to a wiki.