Research over many years has been consistent in showing that pupils often learn better when the subject or lesson is made fun and interesting. Teaching a subject in a way that will make it stand out to your pupils can be enough to help them remember the important information taught to them.
Often teachers say that they run a usually hard lesson or boring lesson outdoors or in a totally different way to that of which the pupils are used to. This can make them enjoy learning and therefore they are more likely to stay focused on the subject matter. Often giving them physical experiments to do, or showing them videos can also help learning as seeing something in action can be easier to understand than just reading about it or being told.
If you are struggling for fun ideas for lessons, then have a look online where you will find a wealth of information from other teachers or teaching organisations.