I tried rooting a cutting and was unsuccessful. Would like to hear what others have to say on this as well!

The first thing and likely the most important step is to use sharp tools. Acer in general has a thin cambium layer, Japanese Acers are very thin! Sharp shears and if grafting sharp knife will be critical.

Once cuttings are taken the sooner they are stuck the better!
I use and have used powdered Root Tone with good success. Placing cuttings in to pearlite that is watered once to twice a day, depending on humidity and temperature. They will take four to eight weeks for the root initials to develop. Very gently pulling on the propagules and noting how "loose" they are in the media will indicate rooting. Waiting until very late summer or early fall to plant into pots with well aerated soil mix with good drainage and ability to retain moisture. Use of clay or terracotta pots is always best. Keep the rooted cutting shaded for at least two seasons-(when the tree fills the pot/soil with roots to the point of being able to hold the rootball together when turned upside down. Partial shade during the hottest months until vigorous enough to plant in the ground. Depending on variety/cultivar will dictate sun, shade, or partial. Fertilize with all purpose fert. at half rate from the time of planting into pot until planted in to the ground.

Hc

I forgot to say that the cuttings need to be from "old wood", in other words, take wood from last seasons growth or older. Using green wood will result in failure!

You may also consider air layering. If you go with Air layers make sure to scrap the green cambium from the wood! Otherwise the tree will "jump the layer" and will not root. Use the root tone with the layer as well.

Leave inside in winter or outside well mulched?....Live in Michigan...Thanks.

Hc, what time of year do you take your hardwood cuttings? Do you also use bottom heat?