There are differing levels of light relating to plants. There is full or partial sun and shade. You should really try to plan your plantings relative to the light requirements of your plants. So you should group plants that need similar light levels together. Although if you have tall plants and smaller plants that like shade then you could plant the taller ones over the smaller shade loving plants.
There are other factors to be considered when considering sunlight and the needs of your plants. These are the intensity of the sunlight and the number of sunlight hours. So the plants that need more light for longer periods should obviously be planted in brighter, sunnier areas. Along a Southern facing wall or fence for example.
If you have plants that only flower during the winter months they will need to be planted in areas where the daylight length is longest during the shorter winter days. Rather than planting other plants in those areas.
Light quality also has an affect. Photosynthesis requires certain light wavelengths, while flowers and fruit require other wavelengths.