Question: Should a person residing in Yerushalayim go to Tel Aviv (or the like) to hear Megillah a day early, on the 14th of Adar?
Short Answer: Rav Yosef Dov Soloveitchik zt”l cites a machlokes Rambam and Ramban whether the 14th or 15th day of Adar is the main day of Purim. This author suggests that if the 14th day is the main day, perhaps it is preferable for someone in Yerushalayim to hear the Megillah on 14 Adar.
Question: How does one do t’shuvah for speaking lashon ha’ra?
Short Answer: One who speaks lashon ha’ra and causes damage to the person being spoken about must seek forgiveness from that person, as well as following the regular t’shuvah process for sins between man and Hashem. He should also learn Torah.