How do you get the most juice out of a lemon?

I'm curious, how does one effectively extract the maximum amount of juice from a lemon? Is it simply a matter of squeezing harder, or is there a more strategic approach to getting the most out of your citrus fruit? Are there any tools or techniques that you've found particularly effective in maximizing juice yield? And lastly, are there any considerations that one should take into account when selecting a lemon to ensure the best possible juice extraction?