Preferences are just that: things you prefer. They're not essential, but without them, you could end up with a landscape you don't love.
Here's a list to consider. Note which items would be priorities for you, and which ones preferences.
Colors - likes & dislikes
Plant Materials - likes & dislikes
Entertaining Spaces:
Patio
Deck
Pool
Utility Areas:
Vegetable Garden
Compost area
Dog Run
Water Features
Wildlife Attraction
Deer-Resistant Materials
Privacy
Retaining Material
Low Maintenance
Drainage solutions
Room for Sports
Basketball Court
Baseball
Soccer
Volleyball
Bags
Energy Efficiency Issues:
Windbreak
Shade