Here are some of the stumbling blocks I have had: I don't know anybody there. I don't know what I would like. What if I get pushed to do something I don't want to do? How do I know what I would be good at? What if I get asked to do something scary, like talk to strangers or be around scary people? Everybody else seems more affluent than I am and I don't want to feel pressure to give money I need for other things. Aren't I too young? Aren't I too old? How will I fit it in?
Does any of that seem familiar?
Let me share some ideas from my experiences in this area: Ask someone you know, even a little, and ask them about where they volunteer and if you could help. Spend a little quiet time thinking about what touches your heart and then do a little research about who needs help. Look at the groups at your church who have a mission they support and ask someone to tell you more. (Asking questions does not commit you to participate further and keeping the mission of your church family on your prayer list is good for everyone!) Try something just once. Try something else. Promise God that for 30 days or 6 month you will be a willing helper for anything that you can do even if is seems too small or is not really your area of interest. (This last still makes me giggle because God has provided many unexpected blessings because of my offering this to God!)
So, what if you find the mission folks ask for things you are not willing to give? If they are truly pushy and obnoxious you may need to keep looking for the right place, because, frankly, some church people have a lot of growing to do. But maybe they are speaking God's call to you. So pray a bunch, including for the people serving the group and being served by the group, asking God to send you wisdom and discernment about your place in the ministry.
Oh, does this sounds like work? You betcha! It is also very exciting and fun. You will meet some of God's most amazing Servants. You will have experiences that will change you forever. You will be blessed in direct relation to your willingness to be a Servant. It does not require you to live without life's necessities. It does not usually require that you get on a plane or boat to travel to distant lands, but if it does, oh wow! It does not require that you be young or old or healthy or brainy or educated in some particular way. But it will result in you being amazed at how God has been preparing for your service long before the thought ever entered you mind.
Will you offer yourself to God to use in His Ways for the next month?