Avocados can be tricky to choose, as the size, color, and feel of a ripe avocado can vary by type. Look for avocados that have deep green or black skin (the more colorful the better), but avoid those that are scaly or have sunken spots. Gently press on the avocado near the stem; if there's some give, it's ripe. Ripe avocados will also be slightly soft when gently squeezed. Additionally, you can also try to remove the stem from an avocado: if it comes off easily and it’s green underneath, then the avocado is likely ripe.