Here is an excellent Dua of the prophet that is appropriate for all occasions. According to the hadith of Abdullah ibn Umar, the Messenger of Allah (S) would rarely stand up from a gathering until he had made the following dua for his companions:
“O Allah, apportion for us, reverential fear of You, that shall come between us and disobedience of You; and of obedience to You, which shall cause us to obtain Your Paradise; and of certainty, which shall make the afflictions of the world easy for us; and enjoyment of our hearing, and our seeing, and our strength as long as You keep us alive; and make it the inheritor of us. And let our vengeance be upon those who have wronged us; and aid us against those who show enmity towards us; and do not make our affliction in our religion; and do not make this world our greatest concern, nor the limit of our knowledge; and do not give power over us to those who will not have mercy on us.” [al-Tirmidhi #3502, Saheeh]