The popularity of mobile photography has been bolstered by an incredible array of editing apps that help put the finishing touches on a photo. Filters should be used sparingly, or in the case of apps like VSCO Cam, at 10-30% strength, as they quickly can make food look odd.
Increasing the brightness and sharpness can add depth to an image. Contrast and saturation should be adjusted ever so slightly–they can help emphasize the food, but can also easily go in the wrong direction. Making adjustments to highlights and shadows will help correct any lighting issues. One of my favorite apps, Snapseed, allows adjustments to specific areas, which can help make a drink or dish pop further.
As with all photography, practice makes perfect. We eat at least three times a day, giving plenty of opportunity to explore how to take better photos of food.