When planning and executing your experiments, consider how much material you need.
If it´s an experiment with cells in culture:
Which size of petri dish or flask do you need? What´s the minimum number of cells required for this experiment?
Using the smallest petri dish possible minimises the consumption of plastic, cell medium and ALL the reagents you will be using downstream of seeding your cells.
It may seem insignificant -- but small strokes fell great oaks.
And your boss will surely appreciate that you are using less reagents!