Churches, by themselves, are already beautiful buildings both inside and out.  Old churches with architecture of historical value and excellent acoustics would have completed half the church wedding decorations effort needed for the ceremony.   The most important thing to remember is, first and foremost, to obtain the permission of the vicar before contracting the services of a decorator (or buying the resources if you intend to do it yourself).  As churches are places of worship, permission will usually be granted for minimal décor, with the exclusion of several sections like the altar, side chapel and areas around statues.  Take note of these areas to be excluded from any form of ornamentation as you will have to explain them in detail to your decorator.  In fact, upon exclusion of these sectors, you may find that it may be quite unnecessary to hire one, particularly if the church is not a big one.

The next thing to do is to "measure" the space that is available for decoration.  This is where your wedding guest list comes into importance.  By now, you should be able to have a rough idea of the attendees.  The estimated number of guests will help you to decide just how many pews to decorate and which parts of the church you will wish to make accessible to them.  Some couples prefer a cozy ceremony and thus, will block off the second half or up to two thirds of the church.  Methods of blocking off the sections are varied.  Some decorators use white or colored (depending on the theme of the wedding) bows may be used to indicate pews to be used to seat guests.  Others make garlands of flowers or buy a delicate string of white or silver tinsel to tie along the aisle to block the entrance to blocked-off pews.  Whatever you use to block off these sections, make sure they are not misleading to your guests so they will not have to bear the embarrassment of sitting in the "wrong" seats.

Marking the pews is optional but a good idea to do at your wedding – depending on how many VIPs you will be inviting.  Decorating the pews with different colored bows, ribbons, lace or flowers is one way of ensuring that the correct guests are seated where they should be.  Some groups of segregation are Family (immediate) and Close Friends (first few pews), followed by Relatives, Colleagues and Others with the optional VIP pew somewhere between Immediate Family and Relatives. 

Having ushers to seat your guests would be ideal as long as they themselves are clear on the seating arrangements.

The choice of flowers used for decoration may be themed – some decorators use the same kind flowers that the bride and her entourage will be carrying, albeit in different colors (roses, carnations, orchids) while others use the same main color but in a myriad of flowers (yellow, red, pink).  And even others will use just about every single flower there is available at the florist, creating a slightly looser, more bohemian look to the event.

Main areas for decoration are the entrance, mid way through the aisle and the altar.  While the altar is usually an off-limits area, a floral arrangement adorned in lace is usually allowed.  And as most of your wedding photographs and footage will include the altar, it will be wise to ensure that the altar boasts of a big floral arrangement that is as eye-catching as it is awesome.  As for the entrance, an arch full of flowers, ribbons and balloons may be used with some decorators even inscribing phrases of love like "Me & You" or "Love" on it.  Halfway up the aisle, a smaller arch can be erected similarly decorated but on a more muted scale.  The number of arches to have along the aisle is your choice – just remember, more arches mean more decorations and a bigger budget.

If you are having flower girls carrying baskets of flower petals, be sure to have those baskets decorated with a little bow or lace matching to the rest of the materials used in the ceremony.

Other areas to decorate may include the registration table where the couple will be signing their marriage certificates.  Some churches will do this after the ceremony in which case, decorations may not be necessary.  Otherwise, a basket of "happy" flowers like lilies and daisies will suffice.

No matter what the décor, it is best to choose the type of décor that will match the church’s architecture and culture.  An ultra-conservative congregation, for example, may find arches constructed along the aisle a little too overwhelming.  Whichever your choice, remember that every décor works best when it blends in with its surroundings.