If you do not know any practical skills, learn them now, because when things fall apart you will not be useful and you will not know how to sustain yourself.
What practical skills do you think would be most useful?
I would guess the ability to grow much of your own food would be near the top of the list, but what else?
Skills repairing/salvaging things will become invaluable again. I'm thinking electronics, appliances, clothing, etc. At some point people aren't going to be able to simply throw away something and buy the latest gadget as a replacement. Keeping the machines and goods that already exist in your local area alive will be very good mid term, as you will probably save a good deal of money maintaining the things you have, as well as perhaps making money fixing and salvaging things for the countless people that will not have these sorts of repair skills.
Skills creating new things, mainly in terms of things like machining, metalwork, and carpentry work will also be pretty important. Hell, they're quite useful even now and can be pretty great hobbies.