Read thru or do a search here for propagation chamber. You will find the chamber will help your efforts a great deal. I'm a newbie at rooting too. I read the info bought the supplies and I've got stuff rooting in my chamber right now. I even made an alteration in my chamber. where it says to use glue on the bottom of the pot I used a tight fitting cork. Works just as well.

a zip lock baggie is fine,i blow my air into it and zip it closed. also you can use just a regular pot, soil (stay green aqua control) and stick holes into the damp soil, dip the plant into the rooting horomone, make sure the horomone covers the node (where a leaf comes out, which you will have taken off), put that into the hole, push the soil around the plant, then mist it daily. don't forget to pull the leaves off up to about the first set up. then when you have new growth you'll know. at least thats'my excuse!! LOL water when you need it. keep in filtered light. hope that helps!!
~Medo

You don't say what methods you have used with which plants so it is hard to give you ideas on why your experiments were unsuccesful. Japanese Maples are pretty hard to root but your Hydrangeas will root fairly easily from hard wood cuttings taken almost any time. To give yourself a sporting chance take plenty of cuttings. Just cut lengths of stem 6 ins to a foot long (remove any flowers or flower buds). They don't have to be the ends of stems you can cut up a long piece but it needs to have leaf nodes on it. The simplest method of all is to stick them into good soil in your garden and keep them watered but not sopping wet. Forget about them for a few months and then inspect them. You will be surprised how many will have rooted. A slight refinement is to put them in pots outdoors with or without a plastic bag over them. This method works with many shrubs such as forsythia, philadelphus and even roses. The problem with rooting plants in water is that they often don't make the transition to soil well. Better to start with soil or potting compost.

right now, i just have both in water, and a couple of JM's in peat pots,both methods have used root hormone

maybe i was missing the leaf nodes

i got an umbrella plant (umbrella tree?) indoor plant, i got a small piece of it to take root, and when i put it in a pot, it never did grow, it stayed alive, but for.....6 or 7 months, it was the same lil twig haha.

I root cuttings in my Earthbox year-round. I keep it in the greenhouse so I can easily root cuttings in winter. This worked great for lavender, daturas & lantana during the cold weather and salvia, begonia, abelia and artemsia during the summer. Anytime I have to trim anything, I always stick some cuttings in there. Some work, some don't, but heck, they would just end up in the compost pile anyway!