Always go green, green limes are generally ripe and have more lime flavor than yellowish-green ones.
Feel the skin… Chose fruits that feel heavy, since these have more juice than those that feel light for their size.
How to cut it
First is very important to wash the limes, even if the skin it’s not edible to prevent contaminating the inside.
To obtain the most juice first slice in 3 parts.
Then cut the middle part in sections, this way you will get 100% of the juice.