I've done the elastic trick on a kids sweater, and it worked great.
If, however, you want to knit the cuff tighter, you can put in a lifeline above it, (using a circ works well) cut off the present cuff and pick out the rest of the stitches.
Then you can reknit the cuff on a smaller needle or with fewer stitches.
I had a sweater with a hemmed cuff and I didn't like it. I put in the lifeline and knit ribbing and it worked out very well.