Once you have your knit pieces finished, assemble them by sewing them together. The seaming technique used depends on the type of stitch used in the piece and whether you are making a vertical or a horizontal seam. 

JOINING GARTER STITCH 

Start sewing with the threaded needle at one end of the work

To join two pieces together, thread a darning needle with the same yarn used to make the garment. Place the edges of the garment side by side with the right sides (the sides that people will see) FACING OUT.

Start sewing with the threaded needle at one end of the work

Stitch up the sides as shown, alternating from side to side. 

JOINING STOCKINETTE STITCH ('Mattress Stitch') 

Start sewing with the threaded needle at one end of the work

With the right sides (knit sides) facing you, begin seaming as for the beginning illustration of joining garter stitch. Working from side to side, go under the horizontal bar one stitch in from the edge as shown. 

JOINING SHOULDER SEAMS 

Joining Shoulder Seams Illustration

With the right sides facing you, align the shoulders and insert the yarn needle under one complete stitch as shown. Work inside the bind-off edge for a seamless look.