with any fire making method. The key to actually having a fire is PREPERATION and PATIENCE.
Have all the wood set up so you have from tiny stuff like dry grass, dry leaves, then very thin twigs, then thicker stuff and try to use the dryest stuff you have available. If you set up everything the right way FIRST, when you get an amber or flame, it will be fairly easy to keep it going. Now, if you get a flame and then start scrambling to find stuff to throw in it to keep it going, more than likely your going to fail. Preperation and Patience is te key.
Years of using a fire piston has shown be this the hard way. Now its like second nature.