It all depends on what you have to cut your way through. Personally I would rather hike around much brush than hack my way through it. The number one rule is to be patient if you are hacking through really dense brush. You are not at war with the undergrowth, it's just in the way.
If you let yourself get frustrated you will hurt yourself.
With hanging vines and standing bamboo, I cut down at them at a 45 degree angle. In tall grasses, the kind that will cut you if you try to shove your way through, I just launch the blade at it and let it come to a stop where it does. If you constantly overpower the blade you will have to bring it to a stop with the muscles of your forearm and that will wear you out.
Often when walking through dense brush there will be thin vines that bunch up and hang you up. I put the blade down past my right leg and slice up and away from my body. Never hack down at vines that are hanging you up or you may hit yourself.
When traveling in a line of people through jungle I enforce a rule that only the first guy in line does the cutting. The trouble comes if the second guy is also cutting. The first guy may get tired or loose his balance and reach out to steady himself when the second guy has already started his swing. The sound of fingers falling to the jungle floor would be a terrible sound.

Likewise the second guy has to keep his distance.
Be careful with thorn covered vines under tension. Sometimes you have to look first and cut them in away that they won't snap back and lacerate you. Also lots of jungle plants have irritating sap. If I have to move through heavy brush I make sure I have my sleeves down to protect my arms. Gloves are a great help as well.
One of the greatest dangers in really heavy brush is that you can get turned around and loose your way. Use your compass and mark trees if you have to. Don't rely on your chopping to mark your trail. Lots of times you will cut for a while then hit a clear patch and just walk, shove your way through, find an easier way, etc. Then you get down to where you were headed and find you have to backtrack. You might go a few hundred meters and discover you can't get through, ravine, cliff, whatever. At those times it is helpful to follow a marked trail back out. Mac