Privacy is another factor to consider. You don't want to install your spa under the windows of two-story homes next door. Check your soil type and drainage, and install drain systems from low areas of the yard where rainfall and irrigation runoff is likely. Find our where underground utility lines are for gas, electricity, telephone and sewer. Look to see where your best views are, and use low-growing shrubs and trees there so you don't block that view.
Some communities have strict regulations on landscaping.
You don't want to put a patio in the middle of a public utilities easement, to be dug up. And check what your setbacks are. And mark out these areas on the ground for a visual analysis. They mark it out on the ground and think what you're going to do there. Make it larger.