When a lemon or lime is cold and straight out of the fridge, it is difficult to squeeze much juice from it.
Before squeezing, first roll it on the counter to burst open some of the segments. Then prick the skin in a couple of places with a knife and put the lemon or lime in the microwave for about 20 or 30 seconds. You will be amazed how the juices flow. Just make sure you let the lemon cool for a couple of minutes before squeezing so you don’t burn yourself