What elements of tradition do the citizens continue to embrace in regards to the lottery?

I believe that your question is asking about which traditions the people have continued to use regarding the lottery.  

One tradition is the lottery itself.  The town still draws names out of a box in order to determine who is going to be stoned to death.  That's a disgusting and morbid tradition.  Mr. and Mrs. Adams indicate to the reader that the town must be one of the only remaining towns to continue the...

I believe that your question is asking about which traditions the people have continued to use regarding the lottery.  

One tradition is the lottery itself.  The town still draws names out of a box in order to determine who is going to be stoned to death.  That's a disgusting and morbid tradition.  Mr. and Mrs. Adams indicate to the reader that the town must be one of the only remaining towns to continue the tradition.  

"They do say," Mr. Adams said to Old Man Warner, who stood next to him, "that over in the north village they're talking of giving up the lottery."

"Some places have already quit lotteries," Mrs. Adams said.

Another tradition of the lottery that has been retained for many years is the usage of the black box.  It has been in use longer than anybody can remember, because the box had been in use before the oldest man in town was even born.  

. . . the black box now resting on the stool had been put into use even before Old Man Warner, the oldest man in town, was born.

Once the lottery was declared open, a ritualistic order needed to be followed for the sake of tradition.  Mr. Summers had to be properly sworn in.  He must call up the members of each family in a specific order, and nobody is allowed to look at the paper until everyone has had a turn.  The order is alphabetical. Those traditions are still in place, but they are fading traditions.  The text is clear that many of the traditions are no longer practiced.  For example, the box is filled with paper instead of wood chips.