I feel like everyone at some point or another needs their jeans hemmed. When this happens you have a few options. You can take them to Buckle, Nordstrom, or another tailor- pay about $20 and wait a few days to get them or if you have a sewing machine you can hem them yourself which takes about 5-10 minutes.
However nothing looks tackier then an unprofessional hem.
SO here is a quick tutorial on how to hem your jeans with the original hem. I didn't bother buying matching thread because these were H&M jeans that I got for $9.95 each. However with denim (especially your designer jeans, ladies) make sure to get matching thread!
Here's how to do it!
Lay out your pants. Then lay a pair of pants which you like the length of on top. This way you know how much length you need to loose.
Fold the bottoms of your long jeans up so that the hems of both jeans match up.
Pin the cuffs of both pant legs.
Sew along the seam (or as close as you can) of the original hem of the jeans. Do this to both legs.
Cut the excess fabric off (I usually leave 1/4 of an inch so I can reinforce the stitch with a zig-zag stich or use a serger)
Fold the hem down and press with an iron.