From April 2010 KM: Highlights regarding clothing, conduct:
6 Dress and Grooming: Foreign merchants traveling on the road could easily recognize Jesus' family and other Jewish worshippers who were traveling to and from the festivals because of the fringed edges on their garments and the blue string above the fringe. (Num. 15:37-41) Though Christians do not wear distinctive garb, we are known for dressing modestly and being neat and clean. We should give particular attention to our appearance when traveling to and from the convention and while in the convention city. Even if we change clothes after the program, we should maintain a dignified appearance and wear our convention badge. In this way we will stand out from non-Witnesses and make a good impression on observers.
8 Opportunities to Witness: Many in the convention city will notice well-dressed, clean-cut visitors wearing convention badges, and this may arouse their curiosity, providing opportunities for us to tell them about the convention. One four-year-old brought his copy of a newly released publication to a restaurant after the program and showed it to the waitress. This opened the way for the boy's parents to invite the woman to the convention.
• Footwear: Each year a number of injuries occur that are related to footwear. It is best to choose modest, well-fitting shoes that will allow one to walk safely on stairs, gratings, and so forth
• Fragrances: Most conventions take place in enclosed areas with mechanical ventilation. Therefore, it would be loving on our part to limit the use of strong fragrances, colognes, and perfumes that may cause reactions in persons with respiratory or related problems.—1 Cor. 10:24.
• Restaurants: Honor Jehovah's name by your fine conduct at restaurants. It is customary to leave a 15 to 20 percent tip.