Does anyone know anything about gardening?

I think having a look in charity shops is a good idea for books.

Also there's an old ground force one someone recommended to me which has good basics, albeit a dated style.

The Internet is good, but it's almost information overload.

The best starting point is to work out what you have and then search from there:

• which direction do you face?
  
• where do you get sun/shade and how much?
  
• what is your soil type? (you can buy pH testers cheaply off ebay)
  
• what is your soil quality?
  
• which of the above can you change/which are fixed?
  
• what do you want to use the space for?
  
• what is your appetite for maintenance?
  
  

Your Garden Made Perfect on iplayer is fun for inspiration. Garden Rescue is probably more grounded in reality/useful.