Decorate the entire party hall with the pictures of burgers. Use red colour balloons and drapes for the decors. Hang various artificial buns from the ceilings. You can create a burger bar with lot of burger varieties in it. Place bowls of cucumber, tomatoes and onions at the tables. Place various kinds of sauces in the jar on the burger buffet table. You can make a burger display borad at the entrance of party.