Raised garden beds avoid the problems of poor soil, inadequate drainage and pets running through the plants. Since you don't walk on the soil it doesn't become compacted. That means the plant's roots don't have to struggle to get through hard soil. Weeding is easier since you don't have to bend over quite as much. Build a raised garden bed from fencing material in a day.
Select where the bed will be placed. Vegetables and most flowers need a minimum of six hours of sunlight a day. More is better. An efficient arrangement for a vegetable garden is four raised beds as rectangles set in a cross with a gravel path between the rectangles.
Install the fencing material. Specifically how you do that depends on the type of fencing material. Hammer wooden posts right next to each other to a depth of 6 to 12 inches depending on how high the posts are. Posts of 24 inches only need to be sunk 6 inches. Posts of 36 inches need to be sunk 12 inches. Attach metal fencing such as mesh or chicken wire to posts and sink the posts as above. Chain link fencing is best left to professionals because it has to be stretched. In most cases it's too tall, 36 inches, to be used for a raised garden bed.
Place a 3-inch layer of newspapers inside the fencing. Shredded paper could be used as well. The newspapers kill any grass or sod, keep weeds from coming up and add organic material when they decompose.
Place the liner inside the fencing material if it has gaps or holes. Wooden posts are set right next to each other so there won't be much, if any space, between the posts. Chicken wire fencing has 1 to 2 inch gaps. Mesh fencing has gaps of 1/4 inch to 1 inch. The fencing has to be lined so the soil won't escape. Burlap or coconut fiber works well. The color is brown so it won't be too noticeable. Lay the liner against the fencing. If need be temporarily attach the liner to the fencing with plastic-covered wire twistees. The weight of the soil will hold the liner in place when the bed is filled.
Mix garden soil, compost and purchased top soil in equal amounts. Add slow release fertilizer as the label directs. Mix well and fill the raised bed with the mixture. Water to settle the soil when the bed is half filled and then again when it's completely filled.