I attempted this feat with Mary Clare's dress 2 years ago, but I wasn't so successful (there's a small photo of my attempt on this post). Here are two different posts with photos of how it turned out after we brought it to a seamstress to add the sleeves.
This year we were on a bit of a time crunch, and in a different city from the previous seamstress, so I was determined to figure out how to do it myself. I did a lot of Google and Pinterest searching as to how to add sleeves, and here's what I came up with! Please note that I am NOT a seamstress, nor do I know any technical sewing terms. I don't measure and can't sew a straight line. But I did it!
Here's the dress to start with.
Lovely lace and beading.
Here was the pattern for the sleeve I made out of striped fabric.
NOTE: This fabric is folded in half on the horizontal line.
I checked the size by pinning it on the dress. The curved part goes along the dress and the straight side of the sleeve (the part folded in half, so it doesn't need a seam!) is the outer part.
Then I used the pattern to cut my fabric. I guess it'd be considered a chiffon fabric.
It was about $8/yard and I only got 1/4 yard
(it was barely wide enough once I folded it, though!),
plus I had a coupon for 20% off my entire JoAnn's purchase.
I always check the retail coupon list on Surviving the Stores when I'm shopping!
So including the thread and ribbon, this project cost about $3!
I think the seamstress was $20-30 last time.
Here's the sleeve, and I cut out two of them.
Remember that it's folded in half on the horizontal line there, so it's a double layer of fabric.
Then I did a running stitch along the curved part of the sleeve
(I think that's what it's called, you just sew up and down).
Here are both sleeves after sewing the running stitch
and pulling the fabric in to gather it.
I tried to match the two sleeves as much as I could.
I used my sewing machine to sew the sleeves onto a ribbon
I noticed the seamstress did this last time.
Here are the two sleeves sewed onto the ribbon. I figured the scratchy edges
wouldn't bother her as much under the ribbon.
Next, I pinned the sleeves on to try to make them look alike.
I ended up taking out the right one and ripping the seam off the ribbon
so I could gather it again and copy the way the other was gathered.
My 2nd try made it look more similar to the left sleeve.
I had Ellie try it on with the sleeves still pinned to make sure
that it looked okay and that she could move her arms.
Finally, I turned the top of the dress inside-out
and sewed the ribbon on by hand, just going through one layer of the dress.
Here you can see how far in the back part of the sleeve is on the dress.
I felt like the cap was too high and poofy otherwise.
Maybe making the sleeve pattern differently would help with this.
And here's what it looks like!
It's not perfect, but I think it will work.
As my seamstress sister-in-law said,
"For kids, don't worry about it unless you can
tell while they're riding horseback!"
I'll add a photo of her in the dress once I have one!
I hope this little tutorial can help someone else!