You didn't reveal the species or cultivar of your Holly. Many Hollies are very difficult to root, but many are extremely easy. I have had a high degree of success by the use of a mixture of PRO-MIX and PERLITE (1:1), ioooppm of IBA in talc, and bottom heat with mist if you have it. A thin sheet of polyethylene film works just about as well as mist. Rooting generally requires about six weeks-sooner or longer-depending upon time of year. I would also recomend a peek at a good text on roting hardwood cuttings;most libraries have several.
Good Luck!!!

I made a mistake. These are American boxwood. I wish we could edit our posts..

Hey, now is the time to do your hardwood cuttings, during the winter...You can also do them in the spring. You have several options.
1. Take hardwood cutting now.
2. Trim back your boxwoods to spur new growth and take softwood cutting in the spring.
3. Just wait until spring and take some cuttings.

I would opt for solution number 2. When you trim your boxwood, it will encourage much more growth next year, even if it does look ugly than it already does. That way you can make cuttings with a higher success rate and faster growth. It doesn't sound like your 100% sure what the difference between hardwood and softwood is, so check out the site below, he explains it perfectly! Also here is a good video that I found on his site...

Here is a link that might be useful: Shrub Propagation