Young Hemingways in the class are free to use any appropriate format to realize these goals, but the rest of us should seriously consider following the general outline in Step 8 in the description of Presentations. The summary should be written for an audience of people much like yourself, avoiding jargon and defining any terms you wouldn't expect your colleagues to be familiar with. A sample is included at the end of this document. Each paragraph should have a goal. If a phrase does not contribute towards the goal, then it detracts from it and should be deleted.
Many people profit from writing an outline before attempting to write deathless prose.
Brief reports will be used for those labs in which you are provided detailed protocols. Full reports will be used for those labs in which you devise much of the protocol. In either case, the audience for which you are writing consists of people like you, before taking this course. Begin with a reminder of what the goal of the experiment was and what methods were used to achieve that goal. A few sentences should suffice.