While most weddings take place in a church, there is no one way to decorate a church for a wedding. The way the church is decorated will depend on the rules of the church, the personal tastes of the couple and the budget you have for the wedding.
Focus much of the decor on the front of the church. This is where everyone will be looking throughout the ceremony, making it the most important area of a church wedding. If you have a very small budget, concentrate all of your decorating efforts toward the front. If your budget is larger, the bulk of that budget will still be spent on the front of the church.
Place flowers in the front of the church. The size of the church will probably dictate how many flowers you can fit there, but most people have flowers behind the couple in one or two large arrangements and more flowers behind the other members of the wedding party. If you have the budget for it, having a small arrangement at the inside entrance to each pew is a nice, festive touch.
Put candles at the front of the church near the couple. The candles may be incorporated in the ceremony, or they may be purely ornamental. Some church weddings feature the couple lighting a unity candle, or the person performing the ceremony might light them. Some people prefer a ceremony largely lit by candle light and others choose to use the lit candles as background decor in the church.
Choose fabric in your chosen church color scheme. The fabric will be used to make bows or to be draped as a part of the decorations. The fabric may be incorporated into the flower arrangements as well.
Decorate the ends of the aisles. Some couples use the fabric to make bows at the end of each aisle, while some use tulle or ribbons in their chosen colors at the end of the aisles.
Decide whether you want an aisle runner. Some churches don't allow them, but most don't have a rule against them. The aisle runner is simply a long, narrow piece of fabric placed over the aisle for a more finished look to the ceremony. If your budget doesn't allow for an aisle runner, consider having a flower girl sprinkle flower petals on the aisle instead.
Use flowers on the door of the church. These outside flowers will get guests in the wedding mood even before they walk through the door.