A homemade loose-stone patio is a fairly casual project compared to a poured-concrete patio, but you still want to follow a few basic standards to make sure you can enjoy it once it's done. Getting the patio level is important, so your guests' drinks aren't tipping out of their glasses during your first barbecue. Ensure a level patio by leveling out both the dirt and gravel and sand underlayment before you start laying the stones.
Pound stakes around the perimeter where you want the patio. String twine between the stakes, so it encompasses the outside of the patio area. Set the string roughly 6 inches above the grass.
Dig up the sod in the patio area, using your shovel. Get the dirt underneath as flat and smooth as possible.
Run more twine between the opposing corners, forming an X pattern over the whole patio area, all of it at about the same level (about 6 inches above the grass, and 8 or 10 inches above the level of the dirt where you dug out the sod).
Hang the string level on the twine between two of the stakes at the perimeter. Move the string up or down on the stakes, until you get a level reading. Repeat for each span of string between the stakes, until all the string forms a level plane above the ground.
Measure from the string down to the dirt at various points, using a tape measure. Use your shovel to move the dirt around and pack it down until it's within about an inch of being the same distance from the string at all points.
Lay down weed barrier over the dirt. Pour gravel over the weed barrier, to a depth of about 4 inches. Pack the gravel tightly with the back of your flat shovel, moving it around as needed so it's all the same distance from the string.
Pour sand on top of the gravel. Move it around with your shovel, until it's all the same distance from the string.
Spray the sand with a garden hose, using a fine spray setting so it doesn't disturb the surface of the sand. Soak the area and let it drain and dry. Repeat three or four times, until the sand is tight and compact. Let it dry overnight. Lay your patio pavers over the sand.