Most commonly delivered by the Best Man & Maid of Honor, the wedding toast is a public speaking opportunity, that if done correctly, will WOW the guests and honor the bride and groom. Infusing humor into the toast that is in good taste is also suggested if you have that spin.
Tips to Deliver a Great Wedding Toast

1. Duration- 3 – 5 minutes per speaker is a good standard and if more than two speakers will address the mic, keep this on the lower end of the range.  A solo speaker can extend a little beyond this range.  Speeches that are too short appear as “off the cuff”, while long winded speeches seem self-indulgent.  Extended speeches (prior to dinner) also delay the meal for which the caterer may have been keeping warm for some time.  
2. A Roast is tempting, but make it a Toast- Keep any humor and poking fun at the bride & groom light hearted.  Reserve the embarrassing stories for the bachelor and bachelorette parties. 
3. Use humor to break the ice- Put yourself and your audience at ease by opening with a joke, then get into the heart of your toast. A toast I will always remember was one in which the brother of the groom and best man opened with a story of his obsessive compulsive brother, the groom. As a younger man, the groom checked the stove multiple times to ensure it was turned off before leaving the house.  From under the table, the Best Man retrieved a small toy stove with all knobs pointed to the off position.  As you can imagine, this generated quite a response from the guests and set the stage for a smooth delivery of the toast. 
4. Rehearse your delivery – Prepare an outline (a) Opener – Introduce yourself and describe your relationship with the bride & groom, (b) include a joke, (c) (best man) direct some comments toward the groom (maid of honor) direct some comments at the bride.  (d) discuss how their relationship together is greater than the sum of the individual parts, and offer some advice and words of wisdom (e) ask the guests to raise their glass, and offer a brief toast such as "May your love be strong enough to survive the times and old-fashioned enough to last forever. Given the outline you have prepared, create content for these sections and rehearse until you have a well polished speech. Be sincere in your words and success will be yours.  
5. Hold the Microphone Correctly –The majority of mics used at wedding receptions are Cardioid Unidirectional Microphones. They are sensitive to sounds emitted from only one direction (your mouth).   Position the microphone towards your mouth but not touching it, about an inch away. Speak clearly and in a firm, clear voice and the microphone will perform well. Don’t shout or hold the microphone too low.  Most DJ’s will adjust the volume accordingly to take into account, these missteps, and/or for the soft spoken. 
6. Have your glass poured and on deck- Be prepared to raise your glass when you ask guests to raise theirs.  This may sound like a no brainer, but I have observed a speaker on more than one occasion scramble for their glass, quite embarrassed.