When you ask for volunteers in public, you rarely get any. And if you do, they are likely not the ones best suited for the work. You end up angry that those who you really wanted didn’t step up and you are left in the embarrassing situation of having to tell someone who just volunteered that you don’t really want their help.
Same goes when you put some work out for comment in a general way. “My plan for this project is attached. Please have your comments to me by the end of the week.” This rarely gets you the input you wished for and often gets you input that is not very helpful at all.
So how do you get the right people to step up and help you, or to give you input on something where you know their knowledge would be helpful? You ask them personally.
When you ask someone one-on-one for their help they are sometimes flattered, sometimes surprised, but almost always willing to help. This is my experience. I am not just speaking of situations where I have authority. I am talking about asking for volunteers from among my peers in various community activities. A direct ask works much better than a general ask.
How do I know this to be true? Personally, I rarely volunteer for anything when I see a generic ask. But if I am asked directly by another human being, I will at the very least think it over and am far more likely to say yes.
Same goes for getting my input on something. Send a question out to a bunch of people including me, I am not very likely to give input. Ask a group of people including me to review a large document and provide feedback and I likely won’t do it. But if you personally invite me to a meeting to go over a specific issue, I am in. I will show up and do what you ask when you invite me personally, explain the need well, and frame the experience for me. When I feel you have made the effort to respect my time and expertise, I will be far more likely to help you in the future, too.
My advice? If you want to get people helping you get stuff done at work, at home, and in your community, ask them personally and make it easy for them. When you get a bunch of people helping you this way, you can really get stuff done and energize everyone involved in the process. That is my experience.