I'm always blessed when good, not great, waiters and waitresses at a restaurant serve me. It's easy to tell the good from the bad by how well they serve without being asked. There is something about the waitress who is attentive to the table's needs: filling the water, keeping the kids' napkin supply coming, keeping the coffee full, and generally being available to serve you well. They are near, always observing, ready to act at a moment's notice.
"Jesus said to them, 'My food is to do the will of Him who sent Me, and to finish His work. Do you not say, 'There are still four months and then comes the harvest'? Behold, I say to you, lift up your eyes and look at the fields, for they are already white for harvest! And he who reaps receives wages, and gathers fruit for eternal life, that both he who sows and he who reaps may rejoice together.'" John 4:34-36 (NKJV)
Serving in the ministry is very similar. You will be very effective if you attentively open your eyes. One of the best practical things you can do to improve your service is to be very observant, expectantly ready to take care of things that need to be done, without waiting to be asked. As you open your eyes and look around, you'll see all sorts of things that need to be done. Does the trash need to be emptied? Is there trash in the parking lot? Has a wolf in sheep's clothing showed up? Are the chairs crooked? Is there distress on someone's face, joy on another's? Is that a brand new family to the church and do they need some help? These observations are all promptings for things to be taken care of.
With eyes wide open, Spiritually sensitive to the situation, you'll have more ministry than you can possibly handle, ministry that the Spirit of God will direct you in. As you're observing, put yourself in the shoes of those you're serving and ask yourself: what would help them be most comfortable, ready to receive the Word from the ministry? If you were a new family what would help you? If you were that Jr. High kid, how would you best receive? Put yourself in the place of every kind of person who comes to your church and prayerfully ask God to show you what needs to be done and seek to fulfill that if at all possible. Don't wait to be told to do something, but instead, always be on the look-out, seeking for ways to serve and then do them. You'll be blessed and so will the precious folks put under your Spiritual care.