First of all, we would like to stress that Istikharah prayer is a two-rak`ah non-obligatory Prayer by which one seeks Allah’s guidance when he is confused or can’t choose between permissible alternatives. In this case, the Muslim should pray to Allah the Almighty to guide him to whatever He sees fit for him and make his heart satisfied with the decision. A Muslim is permitted to repeat Istikharah until he become quite sure about his choice.

In this regard, Sheikh Muhammad Nur Abdullah, ISNA President and Member of the Fiqh Council of North America, states the following:

“If a Muslim is confused about choosing between two things, he is supposed to pray Istikharah but it is not necessary to see a dream in order to know if the Istikharah is positive or negative. The bottom line with Istikharah is tranquility and comfort a person finds in his heart after the Istikharah and that the thing he chose is made easy for him and there is no obstacles.
If someone cannot determine his feelings, he is allowed to repeat the Istikharah as long as he would feel comfortable. `Umar, may Allah be pleased with him, after consulting with the Prophet’s companions about taking a certain decision, he kept on making Istikharah for a whole month until Allah guided him to choose the right decision.
therefore, the whole point of Istikharah is to be satisfied about what you are seeking the Istikharah for.”

Moreover, Dr. Muzammil Siddiqi, former head of the Islamic Society of North America (ISNA) and member of the Fiqh Council of North America, adds:

“After offering Istikharah, we may do whatever is best in our understanding or whatever convinces us. One may repeat the du`a’ of Istikharah several times if we are still hesitant. It is not necessary to dream about anything and we do not have to wait for an answer in our dreams. It is reported in a Hadith that the Prophet (peace and blessings be upon him) said: “O Anas, when you intend to do some important things, then seek the good (seek Istikharah) from your Lord seven times and then do that to which your heart (or mind) is inclined, because the good is in it.”
Most of the hadiths on this subject do not talk about any dream. However, the famous Hanafi jurist Ibn `Abdeen has suggested in his Hashiyah that one should make the Istikharah Prayer before sleeping, and should sleep after having performed Wudu’. The face should be towards Makkah. If one sees something white or green in one’s dream, then the answer is yes, but if one sees something dark or red then the answer is no.
Other jurists of Shafi`i, Maliki, Hanbali and Ja`fari schools say that one should do that which is most convincing. According to Imam Malik, other people can also perform Istikharah on behalf of someone.
there is nothing strange about dreams. If you did not see any dreams, then it does not mean that dreams do not occur. After the Istikharah Prayer, some people may see a dream and some may not. We know that some of our dreams become true. Some time we see something in a dream and it happens exactly the same way later. As there are good dreams and bad dreams, so there are also true and false dreams. The interpretation of dreams is a special knowledge that some people have. In the Qur’an many dreams are mentioned. Prophet Ibrahim (peace be upon him) saw in his dream that he was sacrificing his son. Prophet Yusuf (peace be upon him) had dreams and Allah also gave him the knowledge of interpreting dreams. Prophet Muhammad (peace and blessings be upon him) also sometimes interpreted the dreams of his Companions.”