The first job in any garden design is to lay armoured cable round the garden. Avoid using a low voltage supply and use mains voltage power for garden lights, plugs and water features.
It is money well spent.
Create sheltered and peaceful seating areas. These can be useful for adding height in a garden design by adding trellis work round part of them.
Add the sound of running water with child friendly water features.
Create meandering paths to lead you round the garden.
Add hard landscaped areas for additional seating.
Add scent to the garden by using carefully chosen scented plants.
Construct borders and raised beds and plant carefully chosen herbaceous plants.
If you have a larger garden with trees, why not create a tree house - the kids will love it and the adults will too.
Look after your plants and garden grounds and treat this valuable space as another room to your home.