LINDA BENSON Special to The Jewish News T hose parties that mark life's important milestones often present special chal- lenges in decorations. The venues, synagogue social halls, hotel banquet rooms, restaurant private party rooms, country clubs and sports facilities, are usually too plain, too big, or located in the basement. So, how do you go about trans- forming an indoor tennis court into a warm, festive setting for a bat mitz- vah, or a hotel banquet room into the smoky, sexy 1920s Cotton Club? How do you bring your own person- al stamp of elegance, fantasy, nostal- gia, tradition, or the rustic outdoors to your special event? Some area party planners, florists; and designers divulge their secrets of successful party decor. "We have about 40 to 50 party venues in the greater Detroit area that we know like the back of our hands," says veteran party planner Janice Cherkasky, co-owner of Gourmet Parties. Cherkasky, who has been planning parties for 18 years, estimates that bar and bat mitzvahs currently make up 2/3 of her busi- ness. Many families choose special themes that represent their child's Gourmet Parties decorated for the Gershenson bat mitzvah at Temple Israel. 3/20 1998 Cu