Match plant size to pot size
A plant that becomes large above ground may also need substantial root space. Read variety information and avoid crowding several large plants into a container that cannot support them.
Use supports where helpful
Tomatoes, peas, beans and other plants may need stakes, cages or trellises depending on variety and growth habit. Install supports before the plant becomes difficult to handle.
Grow what you will harvest
Space is valuable in a container garden. Give priority to vegetables and herbs you regularly use rather than planting something only because it appears on a generic list.