Shorten sleeve with shirring elastic by stitching upwards from hem, or around the sleeve.  This will gather the excess fabric and create a gathered effect.

If you have a sleeve that is too long, a quick option is to sew elastic onto the inside arm seam or shirring elastic upwards on the sleeve.  This could be at the end of the sleeve starting from the hem and working up towards the underarm, or it could be from the inside arm seam stitching AROUND the sleeve.

I always find it easier to open seams or hems, so that the shirring begins at the edge of the fabric, rather than having a join that can be seen.  It also means that when the inside arm seam or hem is stitched closed it LOCKS the shirring into place.

Another option is to cut 15 cm (6") off the bottom, unpick the hem allowance and the side seams, sew shirring elastic from the hem up the cut piece.  Do this all the way around, then attach back onto the sleeve.

Shorten sleeve with shirring elastic will create a feature at the end of the sleeve.  The shirring will gather the fabric which will shorten the sleeve.

Happy altering
Judith aka genie