There are so many Muslim organizations here in India like Tableegh Jamaat, Maudoodis Jamaat Islamic and others that it is really confusing which one to join. Each have its plus and minus points. As a Muslim in a non Muslim country is it sufficient that I do Islah to Muslims and Da'wah to non Muslims keeping in view the ascendancy of Islam over all the other religions at the best of my ability?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. Working for propagating and serving the Religion of Allah, the Exalted, is a great matter. Allah, the Exalted, praised those who undertake such job and promised them a plentiful reward. He, the Almighty, Says: {And who is better in speech than he who [says: 'my Lord is Allah (believes is His Oneness), and then stands firm (acts upon His Order), and] invites (men) to Allah's (Islamic Monotheism), and does righteous deeds, and says: "I am one of the Muslims.}[41: 33]. And He also Says: {Invite (mankind, O Muhammad) to the way of your Lord (i.e. Islam) with wisdom (i.e. with the Divine Revelation and the Qur'an) and fair preaching and argue with them in a way that is better.}[16:125]. The Prophet (peace be upon him) said: Allah's guiding a man at your hand (through you) is better for you than the red camels (precious kind of property) [Agreed upon]. So, whoever undertakes this duty and helps others do it, whether individually or collectively, is lavishly rewarded by Allah Almighty, so long as this Da'wah (calling for Allah's Path) is done in accordance with the Book (Qur'an), the Sunnah and in conformity with the understanding of the our Salaf (righteous predecessors), may Allah be pleased with all of them. Actually, we are not in a position to judge any of the Da'wah groups, whether the groups mentioned in the question or any others, without a thorough assessment and study of its approach and methodology. Passing a judgement on something is part of perceiving it. On the whole, collective work is a kind of helping and consolidating one another in being brethren in seeking right. So, it is permissible and preferable according to many pieces of evidence proving the excellence of group work and cooperation. Yet, this is not to be taken as a means of fragmentation and division as fanatic parties, with each having its own slogans and emblems, and rejecting right if it comes from other than the group. If the mentioned group adopts the mainstream Path (Manhaj As-Sunnah Wal-Jama'ah) as a belief, methodology, mentality, and conduct, then it is permissible for you to cooperate with it and support it in what is right, but it must be taken into consideration that right is not to be known through men, and that everyone's acts and speech are questionable except for the Prophet (peace be upon him). Obedience to other ordinary men is to be in light of obedience to Allah and His Messenger. A Muslim must also adapt himself to accept right from its source whatever the name and affiliation of this source may be. We advice whomever cooperates with theses groups to be clear and direct in his doctrine and to declare to his brothers in faith that his loyalty is for right and his working with a given group does not necessarily mean that he hates or disavows other groups. Rather, every believer shows inclination and loves according to his piety and obedience irrespective of his affiliation. As for paying homage to a given name, slogan, or person, it is a rejected innovation. And whoever claims right to be paid homage to (or to his group) and exploited the Ahadith (Prophet's sayings) on Bai'ah (loyalty, homage) to be referring to him is an innovator who contradicts the creed of Ahlus-Sunnah Wal-Jama'ah (Mainstream Muslims). What is meant by the Bai'ah mentioned in the Ahadith is that which concerns the general Imam (caliph) that people choose. It must also be taken into consideration that such groups, though aiming at supporting truth and calling to Allah's Path (Islam), they are not equal in terms of their soundness of methodology and comprehensiveness to the different aspects of Islam. Islam is, by no means, limited to any of these groups. They cannot be more than ways of propagating and exposing Islam, by which they are judged. The vast majority of Muslims, including prominent scholars, preaches, and Mujahideen, do not follow these groups. We have to understand the reasons behind the evolution of such groups and to put them (groups) in their right place and not to make means turn to objects that lead to opposite results. As for your question regarding practicing Da'wah with non-Muslims, it is among the noblest duty ever undertaken. Allah Almighty Says: {And who is better in speech than he who invites (people) to (the Path of) Allah?…}[41:33]. To call non-Muslims to Islam is not only a permissible thing, rather it is among the greatest acts of obedience by which one attains closeness to Allah, the Exalted. Da'wah is the duty of prophets and messengers, may Allah gather us all with them on the Day of Resurrection. Allah knows best.