In the Muslim world, the job of the Imam or Shaykh is usually well defined and of a limited scope. He leads daily prayers in a mosque, teaches Qur'an and Hadeeth, and delivers lectures from time to time. For scholars of greater knowledge and fame, their roles are more than likely be confined to traditional academia, teaching everything from Sarf to Usool ul Fiqh.
In the Western context however, it's a very different experience. The Imam may do all of the above, or parts of the above, but is also the marriage counselor, visiting the shut-ins and the dying, the translator and even the janitor. He is a politician, a media consultant, and more.
Moreover, while an Imam from anywhere in the Muslim world is used to a homogeneous audience, sharing the same culture, worldview, experiences and the like, the Imam in a Western nation faces an extremely different situation. Muslims in the West are from a variety of ethnic, sectarian, madh-habi, cultural and educational backgrounds, Add to this those accepting Islam from a completely Western pedigree!
Therefore, we would like to share some points of advice, relevant to Imams but also the governing bodies of Islamic Centers. The advice centers mainly around education. By "education", we mean more than a degree. We mean keeping that knowledge fresh, continued reading on these subjects and introspection.
Items needed for a Western Imam
 Deep knowledge of all the Fiqhi and 'Aqeedah trends within the Muslim Ummah
In the USA you will find Muslims from all areas of the world but also all over the map in terms of their Fiqh, their theological stances, and the like. There should be unity as much as possible among Muslims, and their particular Madhhabi practice[s] should not deter from that. "And hold fast to the rope of Allah, and do not be divided..", says the Qur'an [ Q 3:103].
The Imam can have his choice of Fiqh, to follow what he feels is correct, and he can even explain that choice to the community, but he must always be prepared to see others with slightly different practices and to avoid isolating anyone because of their particular practice.
We would kindly suggest to all Imams, regardless of what particular trend they follow, to be open to study of all the Madhhabs, 'Aqeedah differences, within the Muslim community.
 Other faith traditions
Obviously Judeo-Christian norms are the religious base for most Western cultures. Moreover, since Islam is widely seen as the third in that series of monotheistic religions, it's imperative that the Imam know about Judaism, Christianity and their scriptures, history, impact in local affairs, and the like. If the Imam is not strong in this area, he should never answer queries centered around it. "Answering" questions when in fact one is ignorant of the subject will only make the one answering look foolish, and it makes the Mosque/ Islam itself look bad.
A personal anecdotal story, I brought a Catholic to a mosque for a lecture, the lecturer decided to speak on the Islamic view of the crucifixion. The speaker went on a rant for one hour, making factually incorrect statements, insulting Christianity and Christians in the most ignorant fashion. Obviously it did not make a good impression.
We all have our strengths and weaknesses, but we should not pretend to know if we truly don't.
We live in a world where it is so much easier to obtain knowledge, or at least glimpses on this or that subject. Admittedly Google searches and the like has its strengths and weaknesses, even the study of books can have its limitations, but we should be open, especially if we are going to be speaking to people on faith issues on a regular basis. In addition to religious, cultural and historical knowledge, it's a good idea to become acquainted with counseling techniques, social sciences, take a speech class, seek to understand the local surroundings, the music, and so forth.
This not only makes the speaker a better speaker, it enriches the speaker. The Imam grows spiritually, he grows in Wisdom, as a result of these efforts.
Wa Billaahit Tawfeeq.