If you are looking to have a wedding reception that does not require formal attire, and does not involve a formal dinner where everyone sits in an assigned seat, then consider a cocktail reception.
Here are some ideas to consider when having a cocktail reception:
Bar Layout - Make sure the bar is laid out in such a fashion that long lines keep from forming. If you are offering a drink that is available in variations, be sure to have the necessary ingredients readily available or already mixed.
Work Your Menu Around Your Beverages - For instance, serve hors d'oeuvres that relate to your signature drink. If your signature drink is of Mexican flare then consider your hors d'oeuvres being Mexican flavor.
Encourage Mingling - You do not want everyone at your cocktail reception just sitting around staring at each other. Have several food stations where guests can easily walk up, prepare a small plate and move on. Also, consider have a couple of musicians walking among the guests as they play.
Prepare Your Guests - To inform your guests of the type of reception that you will be having then on your wedding invitation put "cocktail reception to follow." This will give your guests an idea of desired atire while letting them know that there will not be a main course meal.
Your wedding reception should be a time of visiting with family and friends as a new couple. Receptions should be well planned. Small details need to be thought out so that the new couple and guests may share a time of laughter, and create memories and avoid unwanted hassles.