1) Plan your path: make sure your path connects all the buildings, PWPs, and houses. You can do this by taking a picture of your town map then draw lines (to represent path). This will serve as your basic blueprint.
2) Lay a temporary path: dig holes, plant flowers, use any QR pattern to indicate where your future path is going to go. Don't be afraid to try new things in this phrase. This is the trial and error phrase.
3) Choose a path pattern you like and lay in your path: make sure your path is 2 tiles wide. Anything smaller is a hassle for visitors (cuz flowers are easy to trample if the paths are not wide enough).
4) Finalize your landscaping by laying trees, flowers, bushes in neat patterns. Randomized landscaping looks messy.