A Material and Methods section of the report should contain relevant, concisely presented information about the materials examined, apparatus used, and experimental procedures employed. If standard tests were used, then simply reference these standards and state that they were followed. If a modified form of a standard procedure was used, then give the standard reference and describe any significant deviations from that standard. If a new procedure was developed, or if an obscure procedure was used, then you should describe it in detail.
Similarly, if new apparatus or equipment that is significant to the overall project was designed, then it should be well documented. The easiest way to do this is to create a design report and refer to it. If such a report is not readily available, it can be included as an Appendix. In laboratory reports, it is good practice to include a schematic drawing in the main body of the Materials and Methods sections. Schematics are usually devoid of all non-essential information so that readers can quickly grasp the important features.
Present large lists of materials and properties in a summary table. Specify exactly how samples were prepared and any special precautions that were taken. If this is long and complicated, it belongs in an appendix. This is important for persons trying to reproduce your results. This can have important repercussions as shown in these two anecdotes
The discovery of insulin by Nobel prize winners Banting, Best, Collip and Macleod was delayed because of such details. Collip a young biochemist first isolated a pure extract of the life saving material but did not take sufficiently detailed notes of his procedure. He found that he could not reproduce his first success. It took a full year before the complete technique was rediscovered by the team of Banting and Best.
Two graduate students of Dr. Leonard, a chemist at Laval University, were working on a new polymer in the 1990s. Two identical apparatuses were used to measure reaction rates. However one lucky student could instantly create the plastic no matter what temperature was used. The other, try as he may, could not reproduce the results. It was found after a long search that one stopcock in the lucky student's apparatus had been lubricated with a new type of grease. This grease contained a molecule that acted as a superb catalyst. From this we glean not that one should list the chemical compostions of all greases in the report but that minute details such as which grease was used can become important and should be noted.
Remember to be thorough. Include all information required to exactly reproduce your experiment. What seems like a detail to you could be a most important fact in someone else's research.