Ask HN: How to Start Contributing?

Hello HN, I have been working as a Software Developer for a couple years, but never contributed to Open Source Projects yet. I think it is time for me to give back to community, but I find it hard to find a place or project to start and I also think there are people out there want to do this but in the same situation. Are there any "Open Source Contributor Starter Package/Guide" that can help me and the others to get started?