When ironing your seams after sewing them there is a right way to get the best result. The term ironing refers to the way you iron your clothes.
When quilting you flatten a sewn seam by pressing the seam. Pressing is a 'down and hold for a few seconds then lift' motion that does not stretch the seam.
Some people only use a steam iron where as others will only use a dry iron. Try both and use what works for you. Previously I always used a steam iron as I loved the crisp seam effect but I now use a dry iron.
Below is the method that I use, which involves pressing each seam three times.
First, Place the sewn strip on your board with the sewn edge away from you and the darkest fabric on top.
Next, press the seam to set the stitches by placing your iron onto the seam and holding it for a few seconds, then lift the iron and repeat the process along the seam until the entire seam has been pressed.
Lastly, Open up the fabric and use the pressing method above to flatten the seam open. Then turn piece over and press the right side seam.
Step 6: Iron your seams taking care to ensure you iron your seams
towards the darker fabric. Complete your block by sewing seams and
ironing them until you have completed your block.
You are now ready to add your sashing. These are the strips of fabric that are sewn around the blocks. These are added to help blocks stand out or to unify a quilt when all the blocks are different. Some people add them to enlarge their quilt.