Random errors are usually the result of approaching the limits of accuracy for the device used for measurement, and should vary roughly the same amount in either direction (+ or -) from the actual value. For example: a tape measure that is in 1/4" increments is used to measure a length of 3/16". You can mitigate random errors by taking a lot of measurements; as the number of measurements increases the average value should approach the correct value.
Systematic errors are usually the result of an inaccurate measurement device. For example, a measuring tape that has stretched over time. Systematic errors will continue to be wrong throughout the lifetime of the experiment. You can mitigate systematic errors by calibrating your measurement instruments.
Example for #1: Random error: measurements of time for a swing of the pendulum may vary due to the limits of precision of the clock used to measure time. Systematic error: You may have measured the length of the pendulum arm inaccurately before the experiment due to an inaccurate tape measure, which would throw off all of your calculations.
The other problems can be solved in a similar fashion.
