Follow pattern for Selma dress but use 2 strands of superfine/fingering cotton and a 4,5-5 mm hook.
Tension: 10 cm = 9 rows x 21 stitches
Get the rose pattern here, free headband pattern here and free pattern for handbag here (this is just made with cotton and a wide strap (same width as the sides and bottom AND blocked with glue and water after).
The shell stitch edge
First you make sure the dress is closed in both sides (no slits). Then you use 2 strand still but a 6 mm hook and treble stitch (yarn over twice).
Insert the hook in the side of the dress, chain 2 or 3). Make 5 tr around the first row, make 1 sc around the 2nd or 3rd row. How to know where to sc? Put the shell down onto the row and make sure it’s not too stretches or too loose, then make a sc whereever. 5 tr around the next row, 1 sc around the 2nd row or so. Pay attention to the fact that you can crochet around a row (dc stitch) or in the hole between two rows – you do you – you can’t do it wrong. If the edge seems too tight, unravel that bit and make your sc closer to the shell and vice versa.
Then when you reach the beginning just make sure you have distributed your stitches so you don’t end up with two shells directly next to each other.
Now do the same thing for the top of the dress – distribute the shells – it’s OK if it’s not perfect – I for instance have 2 shells on one side of my v-neck but 3 shells on the other side (so I have 5 shells in the neckline spread out) – and it’s OK – it still looks good. To avoid extra length on the strap I just made sure that I made the single crochet on the points of the top of the dress (where the straps would be sewn on). But you can also make the shell on the points if you like.
The straps
Before adding straps make chains and a shell stitch edge (I made 6 shell stitch).
Use a 6 mm hook and two strand of superfine/fingering cotton.
You start with a long yarn end (to sew on the strap in the end). And then you chain.
Follow mine or add more/less chains depending on your size (try it on).
Chain 28, make 5 tr in the 4th ch from the hook, 1 sc in the 5th ch from the hook, 5 tr in the next ch, 1 sc in the 5th ch etc. Finish with 5 tr in the last stitch. Add 6 chains for each shell (or remove 6 chains if you need less).
My strap measures: 40 cm (incl stretch). So 1 shell measures approc. 6,6 cm.
When you reach the end crochet on the bottom side of the row: 5 tr in the shell from the row before, 1 sc in the sc. Finish with 1 ss in the first tr in the round. Try on the strap with a safety pin or something to see it the length fits you, otherwise add more shells/chains. Break off but leave a yarn end to sew it on. Make one more like it.
Sew or crochet the strap on over 4 stitches or so.