If you want to get the most juice out of a lemon—short of using a dedicated citrus juicer, break down the lemon by putting some pressure on it before cutting.

Before cutting them, put them on your counter and roll them back and forth, applying heavy pressure with the heel of your hand. This will help break down the lemon and make them easier to juice. Use a tool like a citrus reamer to get out more juice than you could squeezing with your bare hands.