On asking this question, many may suggest that first we should use the particular piece of code in own project and contribute on that project by raising issues or fixing them. As a beginner, people may start using very popular frameworks like Ruby on Rails or Node.js. Considering it's complexity or maturity, it's extremely difficult if not impossible to start contributing.
I am thinking, somewhere down the line, there is some form of hand holding or mentor ship needed. Where mentor give small task, help in giving some tips or advice, review the first pull request etc. This will definitely boost contribution to opensource projects.
There may be several people providing mentor ship. But I feel it's not structured, how a newbie knows there exist someone who is willing to help. Only way I can think of now is to spam lot of people randomly by looking at their github profiles.
Please suggest how to encouraging new developer to contribute more to opensource and help closing the open issues.