Place a grape leaf vein-side up on a large plate or cutting board. Using a small paring knife, cut the small stem off. scoop out a heaping teaspoon of the rice mixture into the center of the grape leaf. Spread into a thin line leaving enough room on both sides of the leaf for rolling. Carefully fold in the sides and roll it like you would when making a wrap.
Repeat until all the stuffing has been used and place the wrapped grape leaves in a tray.
The trick is to roll it tightly enough so that it doesn't loosen while cooking, but not too tightly since the rice needs room to expand as it cooks.
Line the bottom of a large pot with tomatoes and/or potatoes, and season with salt and pepper. Neatly arrange the stuffed and rolled grape leaves in rows, alternating directions, to completely cover the circumference of the pot. Drizzle each layer with olive oil and season with salt and pepper to taste.
Place a plate about 1-2 inches smaller in diameter than the pot, cover the stuffed leaves. This will hold them down and prevent floating while they are cooking.
Fill the pot with enough water to cover all the leaves and up to the plate. Add the freshly squeezed lemon juice and season with a remaining half teaspoon of salt. Cover the pot and cook on medium to high heat until boiling.
Reduce to medium-low heat and cook for 45min to 1 hour. To check if grape leaves are done, take a grape leaf out and try it.
Once the grape leaves are done cooking, remove from heat and let cool uncovered for 30 minutes. Flip the pot over onto a serving platter. There should be very little lemon water left. Serve warm!