Visiting in smaller churches as often as I do gives me the opportunity to experience a lot of different worship services. It's always easy to tell when some thought and preparation has gone into the worship service and when it hasn't.
This is especially true if I am a guest speaker that day. When I'm speaking in a service where there has been some preparation I can expect to meet with a worship leader about 15 minutes before the service to go over the plan. This person will often hand me a program with my parts highlighted. We usually go over each aspect of the service so I will know what to expect. Often, someone from the church has contacted me a week prior to the service to ask for my sermon title and text so they can be included in the bulletin. The service usually goes very smoothly and has a comfortable feel to it.
Contrast this with a church that does little or no worship planning. I usually have to hunt someone down to ask about their sound system. The pastor or song leader is talking with the pianist five minutes before the service deciding on the music for the service. I was speaking in a service recently when the song leader nodded for me to go to the pulpit to begin my message. As I opened my Bible the sound person said, "I'm loading a video for special music to sing before the message if that's OK with you." I sat back down.
Some churches argue that they don't plan their worship services because they want the Holy Spirit to be free to lead them. I don't think I would blame some of the services I've seen on the Holy Spirit! Besides, I've always believed that He can lead us in a planning process, and we'll usually come out with a better service.
One pastor explained to me one Sunday that the pianist refuses to talk with her about the music until about five minutes before the service begins. I explained that was a power play on the part of the pianist. The pastor agreed but was unwilling to confront the pianist about this unacceptable behavior.
A worship service should allow people to experience God in ways that are meaningful to them. This will seldom happen without some prior planning. There should be a flow to the service that feels comfortable. A worship service is not the time to bring up church business or discuss conflicts in the church. Announcements should be kept to a minimum. Persons who will speak from the platform should be seated in the front pew so time is not wasted while they walk from the back of the church to lead in prayer or make an announcement. Unless there is a quiet time for reflection scheduled, the service should be kept moving at all times.
When I was a pastor I had my sermons planned out a quarter ahead. I made sure our worship leaders knew the titles and texts for my sermons at least one month in advance. This allowed them to plan the worship service to reflect the theme of the message. We didn't do such planning in my first few years as pastor, but when we did start it added much to the services.
When you plan your worship you will be prepared to worship. It makes the experience more meaningful for everyone.