There is a part in each and every one of us that is already deeply surrendered, believing and faithful, already "Muslim", as it were, otherwise the statement that "Surrender (Islam) is the Way back to our True Nature (Ad-Din ul Fitrah)", would not be true. Understanding that "Islam" means "Surrender", and that "Surrender" is the return, through the thick of our fabricated lives, to the authentic truths of our innocence and basically adoring nature, makes it very easy to comprehend and put into practice. "Islam", in Arabic, is a command and means, "Surrender" (to God), pure and simple. This is the real meaning of Islam, and that's why there is a part of us, a quality of our soul, that is already Muslim (Surrendered). The rest of the work is simply in maintaining the recognition and honor of that part. 

This Holy Surrender is facilitated even more by the confirming knowledges delivered through Divine revelation, that there not only is indeed a God, only One, (Arabic: Al-llah!), belief in Whom facilitates trust, which facilitates Surrender, but that He is without doubt Merciful, Forgiving and Caring for all His creation. ("Harisun `alaikum. Bil Mu'mineena Ra`ufun Rahim"). 

This message of Truth and Reality was delivered to the point of utter perfection through His Prophet, Muhammad. 

Another article of "being" a Muslim is a simple confession of belief that there is indeed (ultimately) only One True God (Arabic: Al-llah!) and that Muhammad is indeed (at least one) of the true prophets. A deeper understanding of this reality may be acquired later, but this statement of recognition is the lowest common denominator and at least the opener of doors. 

Stating your recognition or willingness to recognize the obvious is what makes you a Muslim outwardly, and coming to really understand it, and know the truth of it in your heart and act upon it according to your understanding is what distinguishes you, In Islam, as a "Mu'min", or a true believer in the whole truth of God. 

This statement in recognition of the obvious is made in the form of a "witnessing" by simply stating that your are a witness to the truth of "la ilaha illa llah" - that there is only one God and Muhammad is (one of His) true Prophets. It need only be said as a simple confession of faith basically stating that, "I, too, am a believer". It is a basic statement of Surrender and equality, and accepted without question by all Muslims. (For more, see "Shahada" - Bearing Witness.)

In Islam, all faiths are recognized and honored. There are no enemies except those who make enemies. Believers in God are believers in God, no matter what their faith. They are to be protected and demonstrate their assistance to the Muslims in their defense of Peace and the "Land of Peace" (DarusSalam - Jerusalem). Disbelief is to be reasoned with or left alone, but not to be persecuted or oppressed, as long as there is no overt action against the land of Peace.