Printing: measure before assembling
Print the test-square page at the required paper size and Actual Size or 100%. Measure both directions with a ruler. A small scaling error is repeated across the whole garment, so do not tape the remaining pages until the test passes.
If important lines are clipped, investigate the file format and printer margins. Changing to Fit may show the whole page while quietly changing the pattern size. The printing guide walks through that check.
Sizing: read what the numbers measure
A ready-to-wear label is not a pattern measurement. Use the designer's body chart, then compare the finished garment at the same points. Check whether the chart shows a full circumference or a flat width. Do not halve or double an unexplained number simply to make it look familiar.
For a closely fitted design, check the fit in a test garment before using the final fabric.
Cutting: confirm seam allowance and direction
Find the seam-allowance statement. It may be included, excluded or different at hems and special edges. Write the exceptions on your working copy. If a line's purpose is unclear, resolve it before adding or trimming anything.
Check the grainline, fabric face and direction of a one-way print. Count the required pieces, including mirrored pairs and pieces cut on the fold. Rotate and flip are different actions: rotating a paper piece does not produce its mirror image.
Marking: transfer information while the paper is there
Transfer the notches, darts, pocket positions and start or stop points needed for construction. Use a marking method tested on a scrap. Before lifting the paper, compare the marks on the cloth with the pattern. Keep notches within the seam allowance and clear of the stitching line.
A photograph of the labelled pieces can help you find the names later, but it does not replace marks on the cloth that need to meet at a seam.
Sewing: match first, then check the result
Before sewing a seam, match the named edges, notches and ends. Confirm that any pocket bag, facing or lining is on the intended side and that a required turning opening is still available.
After sewing, spread the work out before finishing the seam allowance. Look for trapped fabric, an unintended tuck or mismatched horizontal seams. Press as appropriate for the fabric and construction. Pressing cannot remove a sewn-in tuck; unpick and correct that section first.
When something does not match
Pause before stretching or trimming one piece to fit another. Confirm the size and the two named edges. Mark the stitching lines using the allowance specified for each edge, then compare the lengths between matching notches. On a curve, walk the seam lines together a short section at a time without stretching the paper. Check the instructions for intentional ease. If the difference is still unexplained, keep both pieces untrimmed and ask for the missing detail.
1. Identify the two seam lines
Dark outlines are raw edges; clay dashed lines are stitching lines. Mark the matching start, middle notch and end on both pieces.
2. Walk a short section
Bring the start points together at the seam lines. Pivot the paper in small steps to compare the next section; do not stretch it or compare only the raw edges. Repeat to the middle notch, then to the end.