On Tishah B’Av, one may learn only those parts of Torah which discuss the laws of mourning, the destruction of the Beis Hamikdash, or the tragedies which befell the Jewish people throughout history. One should learn these in a cursory manner, and not delve into it (Drush v’Pilpul). Similarly, one should not consult a Rav regarding Halachic matters irrelevant to Tishah B’Av.
The Rebbe Rashab would learn the Sugya of the Churban in Masechta Gittin (55b-58a), as well as Midrash Eicha Rabba. [Some other appropriate things to learn: The books of Eicha and Iyov, the dire prophecies of Yirmiyahu, the third Perek of Moied Kotton, the end of Masechta Taanis in Yerushalmi, the Tzemach Tzedek’s Reshimos on Eicha, and a review of the Halachos of the day.]
As during the rest of the Nine Days, one should endeavour to hear a Siyum. This should be done on a topic which may be learned on Tishah B’Av (such as the conclusion of Moied Kotton).
Needless to say, the obligation to learn Torah at every opportunity applies fully on Tishah B’Av. [Many Achronim bemoaned the lax attitude some people sadly adopt towards learning on Tishah B’Av.]
One should give increased Tzedakah, especially before Mincha. It is proper to give the value of the forgone meals – especially if one is exempt from fasting.
