You can ask 100 of us, and get 100 different answers..the bottom line is..roses are tough..to an extent..whatever medium you use, just remember that too much water is the kiss of death..other than that, people use sand, potting mix, root directly in the soil...coir..there are dozens of media that work, and no "one perfect way"..so if it doesn't work one way for you , keep tweaking your methods, you'll do fine.....good luck..donna

equal parts play sand and perlite with a small amount of peat moss works fine.

peat based potting mix is fine, mixed with 1/3 part sand. the jiffy stuff is probably fine, but mix in 1/3 part sand. i like to use 4" peat pots, and stick 2 cuttings per pot. that way if 1 dies, you're alright. if both root, you can still divide them without killing them. temperature should be 70-75F in the root zone - buy a cheap thermometer from wally world. you can buy a tall plastic cover for a standard plastic horticultural tray, something like "humididome", to keep in the humidity while it roots. use a shoplight or two as a source of light - that is most reliable, and you can run the lights 24/7 once the cuttings has rooted, to accelerate the growth.

It is listed above by Hartwood just above my listing, but go to this site and follow it and it will work. It has for me better than anything I have every used and it is good for rooting everything, not just roses.
Check out Hartwoodroses.com to see a nearly fool-proof method for propagating roses from cuttings.. If you can't get to the site this is what Hartwood said above:

A friend showed me how to make a mini-greenhouse out of a milk jug and a soda bottle, and I began having WAY more successes than failures. When I root like this, I put my jugs under bushes in the yard where they get almost no sun. Most of my rooting is done now in the greenhouse under mist. The temperature in there is over 90 at any given time, so temperature must not have as much to do with it as you may think.

This method, with step-by-step photos and instructions, is posted on my web site. Click on the How To button. Link Below.

Observations, based on my own experience:

Finding a soil-less mix without fertilizer right now is almost impossible. The presence or absence of fertilizer hasn't appeared to affect my success rate.

I use 1 part spagnum potting mix and 1 part coarse perlite to root cuttings.

Rooting hormone increases your chance of success. Rootone is available just about everywhere. You don't need anything expensive -- just plain Rootone is good.

The biggest thing you can do to increase your chance of success is to take good cuttings from healthy, well-hydrated roses. Get heel wood, if you can. It can make a difference.