As for design tools, even experts vary in how they do this (from formal plans to field layout with stakes/hoses, etc). For DIY, it's often more a matter of understanding basic design principles and finding some inspiration ideas that can be implemented well in your own yard.
Agreed, I have a design background so I started with the survey plan of the property then simply overlaid it with see-thru drawing paper.
That way it is accurate and to scale. You can take it with you when you go shopping for materials or talk to a contractor. You can tell right away that it takes at least three 8-ft wide and 12-ft tall, dense, deep evergreen jasmine trees to block the neighbor's view.
Bonus points for said jasmine trees blooming profusely all year long especially when it rains:) and scenting the air. The study is close enough the jasmine scent can be enjoyed when the window is open.
Dense and evergreen are vital if you live in Florida where we dine al fresco at Christmas in 80-degree weather and have noisy, interfering neighbors.
My garden has five distinct garden areas/rooms that are interconnected but are not visible unless you take a walk in the garden.
1. Party Central with a gazebo and a large, loudly splashing fountain shaded by an old oak tree - complete with outdoor lighting and speakers.
You can only reach it (or so it seems) via an arched walkway cut into a tall evergreen hedge.
2. Secret Garden, well hidden for privacy, with a bright color whimsical small shed, obscure, recycled unique ornaments, a plant hospital and display area for all my favorite shade lovers like gigantic white peace lilies, tropical pink anthurium, stunning iron cross begonias and lots of airplane plants.
An arch with a sparkly moon and stars curtain leads to a cave-like spot beneath the golden rain tree behind a curtain of purple Bougainvillea.
3. A natural area with a woodland park feeling where the leaves are never raked, the squirrels roam, the birds splash in their Celtic birdbath.
A powder puff tree, tropical cherry bushes, hot pink and white azaleas encircle an artisan-crafted cedar bench/rocker while native ferns have taken over as a good looking evergreen, no maintenance ground cover.
4. My pride and joy - a potager inspired herb/veggie/flower garden that took fifteen years to look like a magazine cover - one project at a time.
Enclosed by a low brick border with a substantial deep white entrance arch, gravel paths, a focal point urn, a vignette comprised of a chair/table, arch, small fountain, and a potting area partially hidden behind an evergreen, dwarf red puffball tree.
5. Backyard - roughly 30 ft deep 40 ft wide - starting over from scratch - so bring on the design inspirations:).
I am not counting the front yard, the two side yards or the back forty near the ditch.
Roots and Wings if you do veggie gardening you might like this youtube video on building a $30-35 large arch trellis from a cattle panel and a T pole. Looks easy enough to DIY. I came across it while I got lost in youtubeland thanks to your suggestion:).
https://www.youtube.com/watch?v=wXOX1nzCnaQ