The dates will never be the same every year. They change according to the new moon. The starting day of Ramadan will be known only a day before. Even Non-Muslims can be involved by exchanging the greetings. For those who are Non-Muslims, wish your Muslim friends as, "Wish you a Generous Ramadan". The phrase 'Ramadan Kareem' is equivalent to generous.
One can also do fasting with Muslim friends during the time of Iftar. And during the fasting time, both men and women should dress conservatively and should never listen to unwanted music. Charity is also a major thing during Ramadan. Eid al-Fitr and Eid al-Adha are the main two annual Islamic celebrations. Eid al-Fitr translates as the ‘festival of breaking the fast’ and it happens soon after 'Ramadan' festival.