The first step is to calculate the dimensions on the inside of the garden bed, which is the length and width that is actually usable for planting. If you bought your beds from a commercial source, then chances are, the interior dimensions are probably a little less than the advertised size.
Circular raised beds with a path to the center (a slice of the circle cut out) are called keyhole gardens. Often the center has a chimney of sorts built with sticks and then lined with feedbags or grasses that allows water placed at the center to flow out into the soil and reach the plants roots.
Raised garden beds add new measures to the experience of gardening. Garden beds that we raise above the ground give the gardener with just a balcony a place to grow flowers or a vegetable garden.
For instance some companion plants for your tomatoes are onions, carrots, and parsley while cabbage and cauliflower need to be kept away. Be sure to rotate your vegetables every year, if you planted tomatoes in the green bed last year plant them into the red bed this year.