Here's what wikipedia says about heirloom sewing:
Heirloom sewing is a collection of needlework techniques that arose in the last quarter of the 20th century that imitates fine French hand sewing of the period 1890-1920 using a sewing machine and manufactured trims.
Heirloom sewing is characterized by fine, often sheer, usually white cotton or linen fabrics trimmed with an assortment of lace, insertions, tucks, narrow ribbon, and smocking, imitating such hand-work techniques as whitework embroidery, Broderie Anglaise, and hemstitching.
So I got a bunch of lace trims from M&J Trimming and Nancy's Sewing Basket and some nice thin white and pale grey cotton and started playing. I've a whole board of inspiration pictures on wikipedia for these heirloom tops, so more and different, more complicated ones are still coming. This was just the practice round with my trusted little two-piece pattern: woven front and knit back.
The key with these is neatness. It's crucial that all seams are straight and that the topstitch for each insertion is straight and runs perfectly parallel to the lace pattern.
Anyway, I'm very happy with how these turned out :)