I have always loved sewing with plaids. Just a few things need to be kept in mind in order to have a successful sewing experience. First of all, take a close look at the pattern of the fabric. The way the fabric is pictured the white stripe is below the small blue stripe. Because of this, the top of all the pattern pieces should be going in the same direction. This is called a one-directional plaid.
I like to prepare the pattern pieces using a ruler and marker and extending the grain line on the pattern piece. Next, draw a line perpendicular to the grain line. It does not matter at which point the lines intersect. Pin the pattern piece to one layer of fabric and cut out. Flip the pattern piece face down, lining up the marked lines as first piece and cut out.
We are now ready to pin and sew. Right sides together, carefully match the fabric stripes and pin through both layers. Use plenty of pins and stitch the seam, occasionally peeking between the layers as you go along to make sure that the fabric isn't shifting. You now have a plaid garment with matched plaids!