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!
There is usually no signatures for newbies, but you can always translate, post info on your blog, make videos etc.
Signature campaigns often suggest you have high profile rank so you should spend some time earning it.
Start searching for interesting new or upcoming ICOs. Read bounty terms. Ask their support questions
You can check an ICO in my signature. They've got pretty decent bounty programme