When once you have started upon an effort at recollection, persevere. The date or face or event that you wish to recall is bound up with a multitude of other facts of observation and of your mind life of the past. Success in recalling it depends simply upon your ability to hit upon some idea so indissolubly associated with the object of search that the recall of one automatically recalls the other. Consequently the thing to do is to hold your attention to one definite line of thought until you have exhausted its possibilities. You must pass in review all the associated matters and suppress or ignore them until the right one comes to mind. This may be a short-cut process or a roundabout process, but it will bring results nine times out of ten, and if habitually persisted in will greatly improve your power of voluntary recall.