Use a square-edge spade to dig down about four inches into the entire area where you plan to put the gravel. Level the bottom of the hole using the spade. Test with a level to make sure it's even.
Smooth the area with a rake. Get the soil tight by pounding it repeatedly with a hand tamper.
Put down a 2 1/2-inch layer of crushed stone and smooth it out with your rake. Compact this layer as well.
Cover the area with landscape fabric. You may need to cut the fabric to fit the area.
Put edging all the way around the area to hold the fabric and gravel in place. Purchase edging for a gravel path or area from a home-improvement center. Tap the edging in place by putting a block of wood over each section and hitting the wood with a hammer.
Fill the area with gravel. Leave about 1/2 inch between the top of the gravel and the top of the edging you installed. Use the rake to level the gravel area.