I live in the fenlands of south Lincolnshire where it is very flat. We usually get mild winters and mild summers. Rainfall is a bit over 20" per year but the water table is quite near the surface because we're at or just below sea level. In winter if the wind comes from the East it can get well below freezing. The coldest I've experienced here is -19C or -2F but that really is unusual.
We have a small plot both front and rear of the bungalow. The front being on the North side and the rear being overshadowed by trees from the property ver the fence. We do get good light on the back wall of the building. We have paths all the way round close to the walls so as to clean the windows & doors with two patios by the back door and patio door.
I am also constrained by the fact that my wife wants to see a lot of flowers from the kitchen window and the garden seat under it. We also have a covered garden swing at the southwest corner of the back garden and she wants flowers around that too. The flower beds are against the back fence with lawn between them and the patios/path.
My immediate thoughts are to make a herb spiral near the kitchen door and garden seat under the kitchen window. Next I would turn the lawn into her flower bed and try to hide a few food plants in there. The empty flower beds would then receive perennial food plants with a couple of dwarfed fruit trees. One of the Hardy Kiwis will go up that warm back wall and the other against our East fence that faces West. As to the front garden, I will try and get it all to perennials with flowers close to the drive, bedroom windows and front door.
I'll save the real planning until after I have done the design course which finishes May 31st. It is up near Aberdeen at http://pri-tap.com/