Draft back stay & cut from heavy muslin or hair canvas if you want to be absolutely bulletproof
Iron interfacing onto back armholes, entire side front (except for seam & hem allowances), bias strips onto back hem
Stitch front shoulder hair canvas pieces to larger hair canvas piece (quilt together with parallel rows of stitching)
Attach front hair canvas thing to center front with permanent basting stitch
Get that thimble out and pad stitch the lapels
Tape the roll line
Tape the front and lapel edge
Take a picture and post it on social media because this looks so cool
Close back darts
Sew back seam in two parts. Baste the part that will form the pleat closed, fold down and press.
Baste the back stay to the shoulders, armholes and neckline
Stabilize waist seam with selvedge strip of muslin (optional)
Stabilize top of coat tail with strip of hair canvas (optional)
Fold, pin and baste pleats on coat tail piece
Sew waist seam and press up. Catch stitch waist seam to strip of muslin (optional)
Sew belt and pocket flap pieces with right sides together, turn and press.
Sew patch pocket top edge to lining, leaving a hole for turning later. Sew side and bottom edge of patch pocket to lining (make lining 1 mm smaller all around to make sure it doesn’t show on the outside). Turn and press.
Fold front welt pieces with right sides together, turn and press.
Place front welt on center front piece between notches. Put pocket bag on top. Match location of front welt and pocket bag on side front piece, pin second part of pocket bag in place. Stitch and press. Pin and sew princess seam up until pocket stitching, stop and continue after the pocket. Stitch the edges of the front welt down.
Place patch pocket and pocket flap on marked locations and attach.
Sew front sleeve seam. Attach cuff facing up until the cuff fold line. Stitch back sleeve seam, careful not to catch the facing. Sew the rest of the facing seam. Turn, press, fold cuff back and baste to keep in place.
Stitch upper lining piece to front facing. Stitch side front lining to front facing. (When using an extra back facing piece, leave top five cm of lining/facing seam unsewn)
Make inner pocket flap, fold and press welts. Mark welt location, pin welts, flap and pocket bag in place. Stitch. Slash between welts. Turn and press. Stitch those little triangle thingies to the welts and close pocket bag. Omg.
Optional: cut under collar on the bias to make it sit nicer. Interface collar stand. Sew collar stands to upper and under collar. Cut piece of hair canvas for under collar. Pad stitch under collar. Sew collar pieces around edge with right sides together, leaving bottom edge open. Turn and press. Fold collar into right shape around tailor’s ham or rolled up towel and steam the shit out of it.
Lining: optional: cut back neck facing from shell fabric to have something nice to sew a label on. Draft separate upper back lining piece. Stitch back seams, stitch darts as tucks. Stitch tail lining to upper back. Stitch shoulder and side seams on lining. Stitch shoulder seams on front and back facing. Stitch lining to facing, connecting the earlier stitching lines. Insert lining sleeves to mentally prepare for the real deal.
Get some shoulder pads or craft them yourself from hair canvas and cotton batting. Set in sleeves, cry, unpick, set in sleeves again. Add a strip of cotton batting to the sleeve head for maximum oomph. Attach shoulder pads.
Pin collar to neckline, matching center back to center collar. Mind the varying seam allowances! Baste in place. Pin facing/lining combo to neckline and front edge, sandwiching collar in between. Stitch carefully around the entire coat, including the bottom edge of the facing (leave the rest of the hem alone). Check for puckers or pleats, trim seams, turn the whole thing right side out and press.
Turn hem up, press and baste into place. Sew hem with an invisible stitch, then hand sew lining hem to coat.
Mark buttonholes on coat front and belt pieces. Make buttonholes and attach buttons.
Remove all basting still present, put on your coat, give yourself a pat on the back and then sleep for three weeks.