Here is a post that Chaya Sara wrote last year with suggestions on what to daven for on Purim.
On Purim, there was a real v'nahapoch hu for the Jews in Shushan. Everything turned up-side down - literally! First there was a decree for the entire Jewish Nation to be wiped out and then suddenly it all changed. The decree was changed so that the Jews could fight back and they won against their enemies!
Here is another link about the power of tefillah on Purim.
Also, today is Ta'anis Esther - the day the Esther asked all the Jews to fast on her behalf and on behalf of the entire nation. This was the beginning of the turnaround and the miracle of Purim. Before she went into the palace of the king, she said Perek Chaf Beis (which is why many people say that specific perek today.) It begins with the words keili, keili lama azavtani - so many times we feel that Hashem has left us and we ask Him, where are you? Why did you leave me?
We all have moments in our lives when we feel that Hashem is hiding and we so desperately want to see His face. We want to understand WHY things are happening. Life can be so confusing and we are searching for answers.
Megillas Esther shows us that even when it seems like Hashem is hiding, He is really there - behind the scenes. The word megillah comes from the root of l'galos - to reveal. And the name Esther comes from the root of nistar - hidden. Because through reading the megillah, we come to realize that yes, He may be hidden at times but the megillah helps us reveal Him and notice Him in the Purim story. So if Hashem is so obvious in the Purim story, then imagine how much He is involved in our own personal lives!!
May each of you be zoche to use the power of this holy day to daven and ask for the right things and may you always feel Hashem by your side!