One effective way to minimize errors in your experiment is to use precise measuring instruments for both force and mass. For example, use a calibrated force sensor or a dynamometer to apply and measure the force acting on the trolley accurately. Additionally, ensure that the mass of the trolley is measured using a precise electronic balance.
By using high-quality instruments, you can reduce measurement errors associated with force and mass, which will lead to more reliable data on the trolley's acceleration. Additionally, make sure to consistently verify the calibration of your measuring devices before starting the experiment, as this will help maintain accuracy throughout your measurements.