You can simply look at the labels at your local garden center (though we encourage organic fertilization for a plethora of reasons) and track down one with a higher nitrogen content. It's usually broadcast across the label as a badge of honor and easy to spot.
Later in the season when your plants first start producing fruit, stop feeding them the extra nitrogen. The plants will stop putting all their efforts on getting buff and put their energy back into making dynamo tomatoes and cucumbers.
It really can be as simple as that, and there isn't much need to worry yourself with more than making sure your food producers have enough to drink and in a constant supply. Most vegetables like to go dry to the touch, just like your average house plant, but chances are that can happen in a matter of hours instead of days, so don't forget to check them often.
(Image: Shayna/Apartment Therapy)