The five basic elements of landscaping are line, form, texture, color, and scale. Line is the edges and paths that steer the eye. Form is the three-dimensional shape of plants and structures. Texture is how coarse or fine foliage and materials read from a distance. Color sets mood and seasonal interest, and scale is the size of everything relative to your house and lot.
Designers work them roughly in that order. Lines and forms are the bones of a yard, which is why a design with strong bed lines still looks good in winter. Color is the easiest element to change and the least structural, so starting a project at the nursery's flower table usually backfires.
You can check how the elements play out on your own lot by generating concepts with an AI landscape design tool.