Angrboda is the mother of three of Loki's children: Hel (or Hela), Fenrir, and Jormungandr; the three destructions. 

Features to include when drawing:

• Short black hair
• Black eyes
• Greenish skin
• Lives in the Ironwood Forest
• She is a giant troll-like creature
• The personification of misery
• Colors: black, green - Splash Color = Purple

Don't depict her as "giant" literally, or gigantic, but roughly the same size as the Gods. Think larger than life, leader/queen of a realm or kingdom. The mythological depiction is a metaphor for reputation, symbolism, and/or what she is known for.