Start from the outside of the plant. The big, mature leaves are on the outside. The tiny, baby leaves are in the center.
Snip the big, dark green ones first. They are the oldest. They are closest to turning bitter. Save the tender inner rosettes for later.
If you only pick the babies, you starve the plant. It needs those big leaves for photosynthesis. Pick the old timers. They’re ready to party in a taco.