Tisha B'Av is the time to start doing Teshuvah.

  It is the time when we learn that Hashem holds us responsible for our actions and we should use this knowledge to make changes in our lives.  Don't wait until it is almost Rosh Hashanah to start thinking about Teshuvah, start now.

Change is always difficult, but the important thing is to start.

From the Shiur "Tisha B'av-connecting to Kinos" by Rav Yitzchak Berkowitz on Aish Audio.