The three blessings recited at night are repeated before the Megillah reading during the day. However, when the reader recites the She-hecheyanu, the third blessing, during the day, he should intend it to apply to the other mitzvos of Purim as well as gifts to the poor, exchanging gifts of food with friends, and the festive Purim meal.

Some communities have the custom of not reciting Shehecheyanu during the day. They therefore intend that the blessing recited before the Megillah reading at night apply to the special mitzvot of Purim which are fulfilled during the day.

If one reads the Megillah alone, only the blessings before the reading are recited. The one that follows is omitted. If one had already fulfilled his obligation vis-a-vis the Megillah reading, and he wishes to read it again publicly for others, he recites the blessings before and after the reading. If one reads the Megillah for an individual, the blessing after the reading is omitted. If the person listening is capable, it is preferable that he recite them.

It is customary to roll the Megillah back into a scroll before reciting the blessing after the reading, for it is considered disrespectful to leave the Megillah open.

If a person who lives in a city where the Megillah is read on the fourteenth of Adar travels to a city where the Megillah is read on the fifteenth [e.g., to Jerusalem] or vice versa, there are many variables that must be taken into account to determine when he is required to hear the Megillah reading. The halachah itself is disputed by different authorities. It is therefore advisable, when one leaves his home on the thirteenth of Adar without intending to return on the same day, to consult with a halachic authority about the proper time to hear the reading of the Megillah, and to fulfill the other obligations of the day.

For the text of the blessings on the Megillah, along with translation and transliteration, click here.