I think the good advice to you is to make your own research to get idea and knowledge on how to find a good signature campaign. There are some websites that you may see some good projects or bounty campaign that are really good to participate.
Newcomer to the market they ask this question, but on this forum there are countless people involved in many different campaigns, if anyone answers in detail and specific will make him are confused and do not know which signature campaign to choose. So I agree with your opinion, learn and analyze yourself.