The word ISLAM has a two-fold meaning: peace, and submission to God. This submission requires a fully conscious and willing effort to submit to the one Almighty God. One must consciously and conscientiously give oneself to the service of Allah. This means to act on what Allah enjoins all of us to do (in the Qur'an) and what His beloved Prophet, Muhammad (pbuh) encouraged us to do in his Sunnah (his lifestyle and sayings personifying the Qur'an).
Once we humble ourselves, rid ourselves of our egoism and submit totally to Allah, and to Him exclusively, in faith and in action, we will surely feel peace in our hearts. Establishing peace in our hearts will bring about peace in our external conduct as well.
Islam is careful to remind us that it not a religion to be paid mere lip service; rather it is an all-encompassing way of life that must be practiced continuously for it to be Islam. The Muslim must practice the five pillars of the religion: the declaration of faith in the oneness of Allah and the prophet hood of Muhammad (pbuh), prayer, fasting the month of Ramadan, alms-tax, and the pilgrimage to Makkah(IF HE CAN) and believe in the six articles of faith: belief in God, the Holy Books, the prophets, the angels, the Day of Judgment and God's decree, whether for good or ill.
There are other injunctions and commandments which concern virtually all facets of one's personal, family and civic life. These include such matters as diet, clothing, personal hygiene, interpersonal relations, business ethics, responsibilities towards parents, spouse and children, marriage, divorce and inheritance, civil and criminal law, fighting in defense of Islam, relations with non-Muslims, and so much more.