This patio has straight borders with sharp angles. To accomplish this look, use metal edging and stakes.
First, spray out your design and dig a trench along the lines, 1 or 2 inches down. Then, line up the metal edging in the trench and, while a friend holds it in place, drive metal stakes through each slot until they sit flush with the edging. Holding a block of wood over the stake and pounding on that will help you avoid scratching the paint off the stake.
Within the border, excavate about 2 inches down. A small rototiller will help to break up the soil and a square shovel will help to level it all out.
Decomposed granite provides a nice base for both flagstone and pavers. Starting in one corner of the patio, add about an inch of the decomposed granite over either a small section at a time or over the entire patio area.
Using the edging as your guide for height and as a starting point, choose a piece of flagstone or a concrete paver with a straight edge. Slide the piece back and forth, working it into the base below until it sits flush with the border and level to the eye (Image 1). Go around the edges and push the decomposed granite underneath with a gloved hand until it sits sturdy. As you lay your next piece and all of the rest, keep the cracks between them fairly small. In some areas you may want to leave larger gaps to fill with a pebble mosaic design later (Image 2).
Once all of the pieces are laid out in place, spread more decomposed granite over the whole patio and use a broom to sweep it into the cracks.
In areas with larger cracks, fill them in with pebble mosaic designs for decorative accents. Dig out the decomposed granite that is already in the crack and fill it back up with dry mortar. On top of the mortar, set pebbles side by side on end so that the narrowest part of the rock is sitting in the mortar. Pack the pebbles in pretty tight, using a rubber mallet to compact them even more. Once the area is filled with the pebbles, use a rubber mallet to push them down into the mortar until they all sit flush with the surrounding stone and pavers. It helps to use a small board over all of the pebbles and then pound them all down at once.
Once all of the cracks are filled, hose down the entire patio. This will do two things: It will activate the mortar in the pebble mosaics and it will compact the decomposed granite in the rest of the cracks. When you are finished wetting it down, you may have to go back and fill the cracks with more decomposed granite until it sits flush with the flagstone and pavers.