It really depends how skint you are. If you can spare a tenner or so a week then you could plant something. Potatoes can be grown in a bucket if you don't have a garden. You can grow your own herbs too and it really does make a difference using, for instance, fresh basil in a tomato sauce or fresh oregano in a moussaka. I always am so happy and relaxed when I am surrounded by living, growing greenery.

Again if we are talking not utterly skint, set aside a day every week to cook something decent so you have a meal that isn't just fuel. Good food is really important for your mental health I think. BBC goodfood is a good online recipe site and they rank by complexity and time to cook reasonably accurately.

Another good one is preserving. You can make really tasty sauerkraut very very cheap. You just need a cabbage, salt and a jar.

There are online tutorials for things like musical instraments or art provided you have those things from when you last wanted to learn but work got in the way.

I'd say your best bet is to create a scedule. We've all been conditioned from a young age via school and then work to follow set routines so it's hard to actually get stuff done if it's not been allocated a set time.

Anyway yeah hope this helps.