How to change colors

     Add another yarn ball when you ran out of yarn,This is called “joining” yarn.  or changing color to your crochet projects to make them stand out. This is called “Changing” yarn.
     If you want to change colors, uses the same technique with “joining” yarn

JOINING IN NEW YARN OR CHANGING COLORS IN THE 
ROUND (STEP-BY-STEP WITH PHOTOS)

 TIPS: If this made the last loop of color A too big, pull on color A’s working yarn

 TIPS: Every time you’re supposed to yarn over and pull the yarn through a stitch to draw up a loop, remember to pull the working yarn under any unused yarn and through the stitch

TIPS: If you’re going to use old green yarn in the same or next round, keep crocheting over it. 
TIPS: To minimize the chance of the unused color peeking out, hold the unused color’s working yarn on the inside of the piece.

Q&A

 HOW DO I SEAMLESSLY CHANGE COLORS IN CROCHET AMIGURUMI?
 Because amigurumi is usually crocheted in continuous rounds, each round is a spiral instead of a straight line. This makes color changes look jagged. To make them look smoother, you can replace the first stitch of the round in the new color with a slip stitch.

HOW DO I CHANGE YARN COLOR WHEN DOUBLE CROCHETING?
To change yarn color when double crocheting or really, any stitch at all:
 1. When you get to the last stitch of the original color, pause before you do the last yarn over of the stitch.
 2. Drop the old color and put the new color on your hook so that the yarn tail is in front of
 your hook. Yarn over, and pull the new color through the remaining loops on your hook.
 3. Continue crocheting in the new color.