Ella,
Try to make a link of the events you study.
For an instance, you want to memorise where the Verzasca dam is, you should open Google Maps and search it in there, you will find it in Switzerland. Hence you will also come to know the map of switzerland, boundaries, rivers etc.
Similarly, read the introduction of any event on wikipedia you want to know like 6-day war, you will observe the dates, belligerents, causes, tenure and lots of relative stuff