Mark out path:
Mark out the path you desire. Make its template on the ground with the spray paint or a rope. Use a tape measure to determine the length and width. It is preferable if you keep the same width along the entire length to give a look of uniformity.
Pack the trench:
Add a layer of crushed stone to the smooth trench base. Pack it done with the rake to form a compact base. Use the rake to create a level surface. Spray some water over the trench to dampen it lightly. Use a hand tamper to pack down the crushed stone so as to make a compact base for the gravel.
Place landscaping fabric in the trench. It should cover the bottom fully. It prevents any weed from growing through. If you are using more than a single cover, both the covers should overlap each other well with no gaps. The shiny side of the fabric should be facing you. Use relief cuts to help the fabric around turns. Use spikes and pins to contain the fabric down and in place.
You need edging around the path to keep the gravel in place. This could be both plastic and steel. The edging should be four inches high. Put a woodblock over the edging and hammer it down so that the edging below it crosses the fabric and secures into the ground. Do it at various locations along the edging. Use a shovel to pack soil around the edging so that it is secured snugly into the ground.
Use your gravel to lay gravel along the path, up to a height that is 1/2 inch less than that of the edging. Use a rake to level off the surface. You have a perfect gravel path now.