Hi Steven First things first, there is no set way to prune japanese maples since there are so many different styles from uprights to dwarfs. i find that each tree has a different manor for pruning. So with hime or most dwarfs I look for the biggest and bushiest. i find "hedge pruning" to be a safe and effective way of pruning but I try and thin back some of the branches at the end so they do not get to bulky at the end. (remember most of my hime and dwarf are 4' and larger so there would be a lot of pruning if i cut it one little branch at a time which is different than a 3 gallon sized tree) As for uprights, I look for trunk and branch structure which is strong and balance with branches alternating on all sides of the tree. Most all the trees i get are 6' and taller in this type. Branches should be going out away from the tree at about a 30 degree angle with mimimal to no branches going into the center of the tree or acrossed the tree. the crossing branches are hard not to find so I just deal with them (hack gone). Since i have been involved with salvaging trees, I have experimented with torturious prune jobsand to the most part I have have very good results. it seems like maples will push extra growth in these cases. Now with dissectums I look for good strong branching. i looke for trees taller than 30" since the foliage droops and any less just lays on the ground. Most all the branches below that will be gone as the tree grows up. I know I can't crawl uder a tree less than that to pull weeds. now on dissectums i try and keep up on pruning them a few times a year. i really like the haystack look so i prune back the new growth on the top of the trees just after is comes out. Yes i loose some of that great spring color. in most cases i try and keep the trees light and airy by removing most duplicating branches. Now with trees like hana matoi or brocade I just leave them a dense bush. ****"IMPORTANT NOTE"**** I DO NOT RECOMEND MY METHOD FOR ANYONE. YOU NEED TO FIND WHAT MEETS YOUR NEEDS.