Ideally, grade lesson plans should be orderly and sensible, but with enough room to include spontaneity and creativity. Anyone who has had to sit through a lesson plan that was rigid and tight, with absolutely no deviation from the tasks at hand, will know that this is a thoroughly unpleasant way to learn. Letting your students breathe a little is important in helping them learn and remember.
First things first, it might be worth checking if there is a specific lesson plan format that you need to follow. Some schools, colleges and universities have a standardised format to follow as this makes it easier for another teacher to use if you are unexpectedly away from work. While there are many different formats you can use for a lesson plan, most contain the same core elements. The title and time of the lesson are basic pieces of information and a list of required materials ensures no essentials are missed out.