When boiling potatoes, add a few drops of lemon to preserve their white color.
When buying lemons for their juice buy the heavy ones, when buying them for the zest, choose the clean and yellow ones.
A pinch of cumin in tabbouleh and with other vegetable mixes helps eliminate the gas produced by some of the greens.
Don't crowd your pan when frying foods. And don't turn the food until it is cooked thoroughly on one side.