We as photographers have an advantage over other vendors involved in weddings in that we always have current images from our shoots to use to promote our businesses with. The same is not true for the florist, bridal boutique, tux shop, caterer, church, reception hall, dj etc., and the quickest way to make other vendors into fans of yours is to provide them with free marketing materials for their business. Vendors other than photographers generally have a hard time collecting good images to use to promote their business. Often they will ask a photographer for some images and the photographer doesn't follow up, so imagine what kind of hero you will be when you get them images they didn't have to chase you down for.
My suggestion is to take a proactive approach and get collage cards into vendors hands within 72 hours of an event that showcase that vendors work. Most of us can't wait to look at images after an event and doing collages just requires keeping an eye out for photographs that highlight the vendors from the event. You'll find it takes very little time to put together the actual collages and you can save your work to use as a template once you have created one collage. I also like to surprise vendors I've never worked with by delivering the cards in person when possible. The cards help create instant rapport with the vendors and you can let them know that you do this as a service for them on a regular basis as long as your info is included on the collage card too.
When creating the collage cards pick 6-10 images that showcase a particular vendors product. For florists of course lot's of shots of brides and bouquet's and table settings etc. For dj's show people dancing and having fun. The collage for the church will have shots from the ceremony etc., see it's easy. Now lay out the collage card using Photoshop or your favorite image editing software. You'll want to grab a logo from the internet of the business or you can ask them to send you one. If you ask them to send one, they'll want to know why and your element of surprise will be gone but some websites don't have a high quality version online. Make sure the name of the business, website, address, phone number and slogan if they have one appears at the top of your collage card. The bottom of the card should have your company's information, logo etc., although your information should be at least 20% smaller than the business you are highlighting.
When your collage cards are finished, print 15-25 of each per vendor and get them into their hands within days of the event. This way they remember the event and are blown away by your great service. They'll figure since you got free promotional products in their hands that you care about your business and those you work with. They'll have instant faith in you and your abilities and you'll be a lot more likely to get those vendors working for you promoting your photography. Please don't tell them the collages only took you a few minutes and cost you less than $5 for all of them, that can be our little secret.
I do recommend you print these in house with a quality desktop inkjet printer because you will be able to get the collages into the vendors hands much quicker then if you have to send it out. Most of today's desktop inkjet printers can print full bleed on popular photo sizes such as 5x7 and hitting the print button is no harder than sending the files to a lab. The papers I recommend for collages are Finestra Art's Premium Luster or Premium Pearl if you want a traditional look. Use Premium Metallic Pearl if you want something with a little more pop to it. No matter what media you choose I'll bet your referrals will never be the same again.
The papers mentioned can be purchased direct at FinestraArt.com and Photography Talk members can save 25% through 9/15/12 by using the code:gofinestra at checkout.