Many of my friends would ask me "HOW". As for me I look for post of upcoming ICO on FB and Twitter. Look them up on Google, which I consider my bestfriend. I look into the coin/ token website. And look for its ANN Thread here in Bitcointalk. Its not easy to start for beginners just like me but I'll learn how to do it perfectly. A little observation, some advice or two from an expert. Making mistakes is normal but we should try to have that thinking of being competitive, the urge to be better if not the best. Being a bounty hunter is challenging. And there's money there too!
You need to promote more to get a reasonable profit from signature bounty campaigns. In this period you can focus on social media bounties as well. They are easier all you need to do is make custom tweets and some retweets.