Select graph paper appropriate for the size of your garden. Paper with four squares to the inch works well. Determine a reasonable scale, depending on the size of your bed. One square per foot is a reasonable ratio for beds smaller than 32 feet long and 24 feet wide, assuming you are using four-squares-to-the-inch graph paper.
Draw a representation of your garden bed outline on the graph paper. Measure your garden beds to the half foot and reproduce the bed size using one square per foot on your grid paper.
Draw in permanent structures that you can't move on your garden diagram, such as fences, buildings, ponds, trees and large shrubs. Other permanent objects include things such as a trellis with a wisteria vine growing on it, a hard-plumed fountain and large stone works such as a wall.
Exclude easily transplantable plants in your diagram. If your bed is already established, you can take some large plants into consideration but you will have to move others to make way for your path. If this is a new bed, you should design the path before adding plants to your design.
Identify what kind of bed path you need. If you just need to weed and prune, use 18-inch steppingstones placed 12 to 18 inches apart, depending on your natural stride. Add a wider path, from 2 to 3 feet wide, to allow you to move garden debris more easily, if the bed is very wide, 10 to 15 feet or more. If you intend to use a garden cart, the path will need to be 3 feet wide.
Draw the path in your bed diagram using the same ratio that you used for your outline. Add side paths to reach between or behind large plants for wide garden beds. You can easily reach about 3 feet to weed.
Select a path material. Make steppingstones of concrete or purchase flagstones. Use mulch for 1-foot or wider paths to prevent soil compression, reduce weeds and add organic matter to the soil. Other potential path materials include bare soil, planks of wood, sunken railroad ties, bricks and blocks.