The main thing is to have fertile soil, with well rotted manure dug in (if you can get it) or else products like 6X, or cheaper Humix.
Test the soil with a test-kit from a garden centre or DIY place, to see if it is acid or alkali, as that will influence what you can grow successfully.
Have a compost bin if you can (it should stand on bare soil), and put all your veg or plant waste in it for making compost. BUT it can be difficult, as ideally a big load needs to be out in all at once, so it heats up and rots effectively.
If you have any neighbours who grow, get their advice, and it neighbours don't use their green waste see if you can have some.
A shredder helps get rid of tree stuff and plant material, and improves compost, but it is a big expense.
Leaf mould can be made (if you have trees shedding leaves) but it is a different process from composting, and takes a lot longer.
See if there is a gardening or allotment club in your area, or the National Garden Scheme (put in your postcode) but there may not be a great amount of activity in winter.
Try local libraries for books, magazines.
On-line, check RHS, BBC Gardeners World etc.