Without the use of the sensors, make sure that you are at least using "set movement acceleration to slow". In this tutorial we will demonstrate why and how this helps us improve the accuracy and consistency of the robot.
This is a 10 runs tutorial that demonstrates how the accuracy of the robot improves when we use slow acceleration vs fast or default acceleration. Note that the improvement is small. This is not an accurate and consistent robot. No. This is a robot that is all but accurate or consistent. It does not use sensors and you should use sensors. But it is a teaching/demonstration moment for everybody to seen what is it that you can expect if you don't use sensors.