OK.
Your garden has good potential. It will get more sun in the summer.
Think about whether you want a cottage garden look, tropical look, naturalistic grassy look.
Do you want a raised bed for veg
Do you want fruit trees
Carol klein took a young couple through creating a small garden on Gardeners World last season, the programmes may still be on iplayer
Look at pinterest to see what you like
Visit local gardens on the ngs scheme to see what grows near you and what people can do with their gardens
I would generally start with the back and the seating and then work on the beds
So up your fence you can have cordon fruit trees in the sunny area, climbing roses, honeysuckle, clematis, winter jasmine, summer jasmine, secured with vine eyes and horticultural wire.
In your veg patch you can have what you like and also raspberries and strawberries, herbs, courgettes, pumpkins beans tomatoes etc
On your patio you need seating and dining. You could have some seasonal pretty planted up pots to start with while you sit and plan your garden. Think about what you will see from the house and from the seat.
Before you plant up think what shape beds you like, keep them wide rather than narrow and after putting down some compost and well rotted manure plant up with 'easy' plants, tall ones st the back and smaller ones at the front. Claire Austin does a few 'perennial borders' mixes of plants, as do thompson and morgan and though you may not buy them they give you good ideas. You can plant up in March. Try to get some all seasons interest.
Look on the rhs website 'plant finder' for what will grow in which season, they sort them by soils and plant colour and shade/sun
Do join the potting shed thread:
You can get good bargains from lidl