The Letter "J"
To make the letter "J," form the letter "I." Then, while your hand is in the "I" position, swoop your pinky finger in a "J-like" motion.
The Letter "K"
To form the letter "K," take your pointer finger and your middle finger, and make a peace sign. Place your thumb between the peace sign. Keeping that form, flip your hand upside down.
The Letter "L"
To form the letter "L," take your thumb and level it with the ground, while your point finger is upright.
The Letter "M"
To form the letter "M," make a fist, and then place your thumb, inside the fist, in front of your ring finger but before your pinky finger.