Consider what the primary focus(es) of the table are (eg. recruiting, charity funds collection) to direct materials and staffing needs.
Connect with point of contact to assure there will be space for table at event, how much space is available, what is the table location (are there security concerns), is their power available, are banners permissible, what days/hours should the table be staffed.
Schedule coverage for the table before the event. Allow for set-up and breakdown time. Confirm who is bringing materials for the table and taking them home at the end of the day. Make sure to allow for suit-up time and breaks for troopers. Allow for an appropriate number of 'bucket off' characters (1-2) for talking with patrons in addition to costumed characters to grab interest and display our works. If you don't have the bodies to staff the table, don't plan the table (consider having an unstaffed table).
While staffing the table be friendly and outgoing to people visiting. Say hello, ask and answer questions, know and discuss the materials on the table. Limit the number of NEGers around the table (don't block the table to patrons). Be professional around the table - you are representing the garrison (don't eat your lunch, air dirty laundry).
Plan in advance table items and placement, don't clutter. Possible items include: fliers, business cards, giveaways (including candy), children's activity books, costume/prop parts, charity fundraiser details, money box.
Consider signage. Ask in the event thread who can contribute a banner. Consider table size/placement and visibility. Ensure that there is a way to hang or tie up the banner (stands, tape, rope, zip ties).