Olivia's cloning gel works wonders. With that being said it all depends on what you are trying to clone. I have found success with batch cloning, because it raises your odds when you make multiple clone attempts. It also can depend on what part of the plant you are taking your clone from too. Traditionally speaking you can take a clone from new growth and propagate it, however, some plants like from the Cannabaceae family, you can only pull clippings from the bottom of the plant because how the hormones are distributed through out it. Water & humidity also can play a key factor in it too. Some plants require root clones. Also, with clippings they will root out of the bottom at the cut point because of the exposed flesh on the inside. If you use a razor and scrap along the sides to expose more flesh, it will give your clone more opportunities to produces roots, versus one single cut point. I would say try many different experiments, I once cloned a grape plant with root tone and a vase full of water.