So the life of your favourite Summer dress is slowly coming to an end. Almost definitely. This one is comfy, you can even shamelessly sit in the lotus position, it's cute, goes with lots I own, is layerable (with tights&cardi it didn't even get a well deserved winter holiday); sometimes I'll even wear it as a kind of dressing gown, first thing to throw on in the morning and mooch around all day in on a Sunday.
... Herein may lie the root of this tragic death: the poor thing is from H&M. Only worn 2 Summers it has outlived its expected life span for a garment from this chain. SO, instead of lament and wail through the nights, I will seek hope in the depth of my soul...
.... and sew myself a new one!
Yup that turquoise one there is the one. Then at least I'd have someone to complain to if it fell apart anytime sooner or later. Easy peasy, really. I googled smocked dress, chose a printed cotton fabric and in it took about as long as running around town, inspecting all dresses, trying them on and never finding the one I had imagined in my perfect summer dress fantasies or if I did it would be too pricey or not available in my size.
This is how:1. The chosen one is a printed simple, light cotton fabric I got from a clear-out of the fabric team at work. Make sure it's not too light i.e. transparent, unless that is an effect you actually want. Mine happens to already be just the width I need, therefore
no fabric at all is wasted, one cut for the length, that's all! Just keep some spare for straps. Then I
hem top and bottom.
2.
Wind the elastic bobbin thread. Now, I read that it has to be done by hand, but it depends on your elastic. It works fine (not amazing) with my first one, a thicker type, until that one runs out. My new, unfortunately different thread type suddenly it doesn't work. I try mechanically winding it, as I would non-elastic thread, and it works! Even better actually, the shirring turns out tighter and more regular!
Test it beforehand on scrap fabric, check the tension and how much it shirrs.
3.
Draw lines on the fabric along which you will do your shirring-sewing with chalk (pencil) or special marker that will disappear later (better option) on the
right of the fabric, as your elastic bobbin is on the other side (obviously).
4.
Shirr away! Drrrr, drrr, drrr, clickclick, snip and
tie a knot at the end so it doesn't come undone.
5. Now, there are different ways of proceeding at this stage depending on the needed width and desired style, but I am keeping it simple for the first born one and
sew the selvages together which creates a single seam along the centre back and also means no edge finishing is necessary.
6. This can already be a finished strapless dress! I'm having mine with
straps however for added practicality, no risk of flashing the general public by accident. I cut one strip ironed it and sewed it.
As I want to be flexible and have an excuse to use
buttons I decide on the strap solution shown above which also means they are detachable (aha, tricky me) and I can get a tan-line free tan if I want to and flash the general public when feeling cheeky! (Never really get that urge though.) I chose azure blue glass buttons from the wonderful Mauerpark Sunday flea market in Berlin I had visited last Summer.
I sew on a little side
pocket as pockets are almost as good as buttons, but I take it off again as I preferred the simplicity. Also, when wearing I found my especially chosen fabric is a bit stiff due to the all-over print but hopefully that will give with lots of wear&washing.
Something I might try next time is the strap solution below (found a while ago on urban outfitters website) but moreover the
shirred panel which means the dress will fit more than strictly one size and through the elastication an opening like a zip (always fiddly to insert) unnecessary.
C'est tout!
The idea of a sewn love letter is metaphorically clever as you want to make those words last as long as possible and fabric is longer lasting than paper. Well, you do have the unpicker in case of mistake or heartbreak. 
For detailed instructions see