Map the space you can actually use
Draw the bed to scale and mark its orientation, boundaries and permanent obstructions. Record where shadows fall during the growing season, where water tends to collect and which edges are exposed to wind. Include nearby walls, hedges and trees because their shade and roots can affect more space than their footprint suggests.
Measure from fixed points rather than relying on a sketch from memory. A simple grid on paper is enough: choose a scale, write the dimensions on the drawing and keep one clean base plan. Copies of that plan can then hold different seasonal layouts.
Design for reach before capacity
Every part of a no-dig or permanent bed should be reachable without stepping on the growing surface. Decide on a comfortable reach from each accessible side and size the bed accordingly. Make paths wide enough for the tools, watering cans or wheelbarrow you use, with room to turn at ends and gates.
Do not count paths, compost bays, water storage or working areas as planting space. Those areas may appear unproductive on a plan, but they prevent compacted soil, damaged plants and awkward maintenance later.
Place height and support deliberately
Put tall crops and permanent supports where they will not cast unwanted shade over shorter crops. The best edge depends on the bed's orientation and the time of day when neighbouring plants need light. Allow room to reach both sides of a trellis for tying, checking leaves and harvesting.
Draw supports at their full expected width, not as a thin line. Climbing beans, tomatoes and sprawling squash can occupy paths or shade neighbours if their mature volume is ignored. Secure supports before roots and foliage make access difficult.
Convert spacing into a layout
Use the recommended final spacing for the variety and growing method, then draw each plant's footprint as a circle or square. Staggered rows can use space efficiently, but closer planting still increases competition for light, water and airflow. Compact varieties may be a better answer than forcing large plants into a small bed.
Plan for the mature crop rather than the seedling. Radishes and lettuces may temporarily use gaps around slow-growing plants, but assign them a removal date so the main crop keeps its intended space. Label every block with crop, variety, quantity and planting period.
Add water and seasonal change
Show the route from the water source to the bed. If using drip lines or soaker hose, group plants with broadly similar watering needs and avoid layouts that require the line to cross a path. Containers and bed edges often dry faster, so make them easy to inspect.
Create an early-, main- and late-season version of the plan. When one crop finishes, identify the next use for that area and allow time to clear residues and prepare the surface. A succession planting plan can connect those bed changes to actual sowing dates.
Check the layout on the ground
Before planting, mark paths, bed edges and major crop blocks with string or canes. Walk the routes while carrying the largest tool you expect to use. Make adjustments now if a corner is hard to reach, a support blocks access or a hose will drag across plants.