Transportation and timing...
Always include a detailed map with your wedding and reception invitations along with contact phone numbers to call in case your guests get lost enroute. It can be difficult to get around in Southern California, especially for out of town guests. A map is an extremely important aid, even in this era of computer map sites and GPS navigation gadgets. Outdoor beach areas in particular do not have street addresses that your guests can simply type into GPS or MapQuest, etc.
When picking a time for your ceremony, keep in mind that sunset is the most popular part of the day for beach weddings. Weekend times around sunset fill up fast. This can put you in competition for wedding vendors to service your ceremony and reception, as well as for wedding guests who live locally and may have to pick between competing ceremonies. Deciding on a late morning or early afternoon wedding can increase your options and lower stress.
Sunrise ceremonies are a delightful alternative you might want to consider, especially if your guests are noted early risers or you are all in town together exclusively for your wedding and time of day is less of an issue. Sunrise at the beach is spectacular. Your photos will be just as dazzling as any taken at sunset. Plus the symbolism of a dawning new day is perfect for the start of your new life together as married partners.
In any case, if your wedding is outdoors where there are no chairs or bathroom facilities, don't make guests wait too long for the ceremony to start. This is especially important if there are older people or small children present.