You can sew the straightest seam in the world & still finish up with a home made look if you don’t press it properly. You really do need to make a friend of your iron. The following three stages will show you how to press a seam to give you a professional finish. This technique works on all fabrics. For all three stages I use heat & steam.
This first stage is very important & lots of people miss it out. On most fabrics you will notice a bit of a wobble on a freshly sewn seam. It happens more on finer fabrics. But on all fabrics this first stage will get rid of this problem. You need to press the seam flat. This will meld the stitches together & set them immediately. Put the full weight of the iron on the two layers of fabric. Steam & press it flat. You want to get rid of the steam quickly to set the seam, use the flat bottom of a point presser & clapper. Or you can hold the seam at both ends & blow the steam through. A perfectly flat seam at this stage makes the following stages easier.
The second stage is to press open the seam. Using just the point of the iron & steam, open out the seam & press just the seam line. There is no need to press both edges of the seam flat against the body of the garment. On some fabrics doing this will result in tramlines showing on the right side. If you are pressing a shaped seam eg. one that goes around the bust, use a tailors ham to help to keep the shape in the seam. You will be left with a sharply pressed open seam but when you turn over to the right side it will look as if you have two humps one either side of the seam. Stage three will get rid of these humps.
The final stage is to press from the right side of the fabric. If you don’t press from the right side your garment will always look home made. Use a silk organza pressing cloth to protect the fabric from shine. Take the weight of the iron in your hand & press from side to side smoothing out the seam. This will get rid of the humps in your seam.
A properly pressed open seam should just disappear in to the body of the garment. This will create a beautiful handmade look to your sewing.