There are many articles about tipping, but the most concise is the one I found on Martha Stewart Weddings. Martha gives a breakdown of who gets tipped and how much which is to say that not every vendor expects a tip. Vendors that own their own business and contract a specific fee such as photographers, videographers, florists, and wedding planners do not expect to be tipped. The best tip that you can give these vendors is a great referral and/or a testimony for their website or a website like OneWed that allows brides to give vendor reviews.
The vendors that do expect gratuity are: officiants, musicians (bands but not DJs), site staff, catering staff including catering manager plus servers and bartenders, stylists, make up artists, delivery people, hotel concierge agents and drivers. Each vendor has a separate rule and some may put wording in their contract about gratuity so always read the contracts carefully. For officiants you can make a donation to their organization separate from their fee, musicians who work independently booking shows should receive $20-$25 per person, delivery people, hotel concierge agents and drivers are all in the same group that should be tipped $5 minimum, and stylists as well as make up artists should receive the same as a regular appointment, 15-20%.
The caterers & site staff should have a section regarding gratuity in their contract. It is either included in the final price or it is not. Gratuity is NOT the same as tax and different vendors separate gratuity from service charge so if you have any doubts, definitely reach out to your contact to confirm. Or better yet, ask your wedding planner to confirm with the catering & site managers. Confirm if the chefs are tipped separately from the wait staff, since this can vary from company to company. Tipping for catering staff can be handled two ways; the tip can be 20% of the food and beverage total only or you can set an amount per server, starting with $20 per person. Catering managers and site coordinators receive more, $50 is a good starting point and make sure you adjust if there is more than one catering manager.
Last but not least, once you decide how much you are giving to each vendor at the wedding, put your payment along with a thank you note in a envelope and seal it up. Make sure you know if the vendor is expecting the tip in cash or by check, specifically for caterers who may have a policy to tip their servers in cash the day of the event. Write the name of the recipient on the front of the envelope but not the amount and give the envelopes to your planner. Oh wait, you don't have a planner? Here is the website of a great one ; )
Don't wait until the last minute
to calculate tips! Source