When knitting a garment in rows, a new ball of yarn or a new color should always be joined at the beginning of the row. The neatest way is to make a reef knot by passing the end of the old ball of yarn from left to right over and then under the end from the new ball.Pass the same end from right to the left over and under the other end and tighten the knot.
When knitting a gurnsey in rounds, the ends of the old and new ball of yarn should always spliced together in the course of working a round.Unravel the ends of each ball and cut away one or 2 strands, then overlay the two ends from the opposite directions and twist them firmly together. The twisted ends should be the same thickness as orginal yarn. work a few stitches very carefully with the twisted yarns, trim away the ends