Drea Leed has made available a smock pattern generator and construction instructions. I use a similar pattern. In Breughel's paintings and engravings, the chemise only shows at the cuff, the underarm, and the hem, so we know they were worn, just not what they looked like.
I always cut the sleeves so that the selvedge is at the cuff - that way, I don' t have to hem them!
Drea Leed has created a kirtle pattern based on the German loose kirtle found in Janet Arnold's Patterns of Fashion. I use a similar pattern but mine laces up the side or sides rather than the back (my lord has knot-tying issues, or rather, un-tying issues!). I find that if I have a lacing ribbon on both sides I can pull the lacing tight and then wrap the strings around my waist, tying them to one side or another. This gives me a great place to hang things from, or to tuck my skirts into.
Close examination of the paintings shows evidence of a kirtle lined in a contrasting color.
I have found that an old linen or wool T-tunic has enough fabric in it for a nice kirtle (and, if you're careful, a set of sleeves or a cap too!).
The bodices of the Breughel gowns vary from the bodices of the Flemish gowns in two ways. First, the Flemish gowns are "missing a bit of fabric in the front", which causes the striking wide laces on the gowns. The Breughel gowns are always either laced (or hooked?) tightly shut or open maybe a total of 2-3 inches.
The second difference is the back of the gown. The back of the Breughel gown has a V-neck, terminating in a back seam (this is very important to strengthen the seam!), and there are also two diagonal seams which originate from mid-shoulder, pass over the shoulderblades, and almost merge with the central seam at the base of the spine. There are many examples of this kind of construction in Breughel's paintings, and two similarly constructed seams from two or three centuries before, represented in two sketches by Hans Holbein the Younger.
From looking at the gowns portrayed in Breughel's paintings, I am quite sure that the skirts were slightly gored. The gowns also appear to be lined - I did this carefully so I could have a reversible dress. The skirts of the Breughel gowns seem to be attached in the same way as the Holbein gowns are, with big organ rolled pleats
Again, I made them reversible so I could wear the gown "inside-out".
Shown here are the front and back of the Breughel gown with accessories
The Breughel partlet is different from the Elizabethan or Flemish partlet in that instead of having a square back it has a pointed yoke (like a choir robe collar) which hangs down the back (conveniently mimicking the seams of the bodice). At least one of the examples in the painting has a metal point on the end of the tip
ALL of the partlets in the Breughel painting are collarless, and appear to be black wool.
The apron couldn't be easier. Simply hem a large square of fabric, tie knots in two corners which share a side, tie ribbons around the knots, and voila! you have an apron.
Flip it over when it gets dirty!