How do I use a paper sewing pattern for the first time?

A sewing pattern assumes a set of conventions that nobody states: pattern sizing is unrelated to shop sizing, seam allowances may or may not be included, and the grain line arrow is the most important mark on the sheet.

What you'll need

• The pattern and its instruction sheet
• A tape measure
• Cheap calico or an old sheet for a toile
• Fabric scissors, pins and tailor's chalk

Step by step

1. Measure yourself properly.Bust, waist and hip, over the underwear you will wear, with the tape level and not pulled tight. Get someone else to do it if you can.
2. Choose the size from the pattern's chart.Never from your usual shop size. Pattern sizing is a separate system and usually runs several sizes larger in number. If you fall between sizes, follow the larger for the bust on a top.
3. Read the whole instruction sheet first.All of it, before cutting anything. It tells you which pattern pieces you need, how much fabric, and whether seam allowances are included.
4. Check whether seam allowances are included.Big commercial patterns usually include them; many independent and Japanese patterns do not. Cutting a pattern without allowance as though it had one produces a garment a size too small.
5. Prewash the fabric.Wash and dry it exactly as you will wash the finished garment. Cotton and linen shrink, and a garment fitted before shrinking will not fit after it.
6. Find the grain line and the selvedge.The selvedge is the finished edge along the length of the fabric. The long arrow on each pattern piece must lie parallel to it — measure from the arrow to the selvedge at both ends to check.
7. Understand why the grain matters.Fabric behaves differently along the length, across the width and on the diagonal. A piece cut off grain twists on the body, and no amount of sewing skill corrects it.
8. Watch for pieces to cut on the fold.Marked with a bracketed line. That edge goes exactly on the folded edge of the fabric so the piece comes out symmetrical and double width.
9. Transfer the markings.Notches, darts and dots, with chalk or tailor's tacks. These are how the pieces are matched up, and they are much harder to work out later.
10. Make a toile first.The whole garment in calico or an old sheet, tacked together. It shows the fit problems while they are still fixable, and it costs almost nothing compared with the good fabric.
11. Cut carefully and only once.Long smooth strokes with sharp fabric scissors, cutting round rather than through the notches. Fabric cut wrong cannot be uncut.

Tips

• Pattern sizes are not shop sizes. Measure and use the pattern's own chart.
• The grain line arrow is the most important mark on the pattern piece.
• A toile in an old sheet costs nothing and saves the expensive fabric.

Common mistakes

• Cutting the size you buy in shops — Pattern sizing is an entirely separate system that typically runs several numbers larger. Choosing by shop size produces a garment noticeably too small.
• Ignoring the grain line — Fabric hangs differently along, across and diagonal to the weave. A piece cut off grain twists round the body when worn, and the fault cannot be sewn out.

If it doesn't work

Questions people ask