The existence of a wedding guide containing advice on planning a wedding and what to do on the day, plus all the addresses of local suppliers of anything wedding related, would drastically cut down any wedding day nerves.
This is something that you could research, write and publish, and bearing in mind there are approximately 5,000 weddings in any big city a year, it is something that could generate big profits.
The idea is that the guide should be stylishly elegant, of reasonably low cost, containing advice, plus a localized directory of wedding related suppliers. This should include the addresses and telephone numbers of jewelers, caterers, florists, churches, specialist card printers and wedding limousine hire firms in your area, plus anything else suitable.
Also useful is advice on organizing a marriage, including a checklist of things to be done beforehand and on the day, an outline of wedding etiquette from engagement to honeymoon, plus the roles of the various participants in the wedding ceremony and at the reception afterwards. A helpful addition would be sample suggestion lists of possible presents, which can be given away.
Obvious points of sale are bridal wear and wedding shops, but because of the nature and pricing of the guide you could also sell it at gift shops and fund-raising events such as church bazaars and fetes.
It should be possible to generate enough income from selling advertising space to fund the wedding guide's printing and distribution costs, thus enabling the cover price to generate plenty of profit.