Use the adjective auspicious for a favorable situation or set of conditions. If you start a marathon by falling flat on your face, that's not an auspicious start.
If something seems likely to bring success — either because it creates favorable conditions or you just consider it a lucky sign — label it auspicious. The word is related to auspice, "a divine omen," an old word with a colorful history. In Latin, an auspex was a person who observed the flight of birds to predict things about the future. Luckily, you no longer have to be a bird-watching fortune-teller to guess whether something is auspicious or not.
adj auguring favorable circumstances and good luck
bright, hopeful, promising
full or promise
presaging good fortune
presenting favorable circumstances; likely to result in or show signs of success