These hotspots are significant because they allow us to locate key areas for focusing efforts at conversation.

很简单的道理，at 跟 efforts 搭配，表示“在...方面的努力”。不跟 focus 搭配，该动词可单独使用，不必一定与 on 连用。

efforts at conversation：“在谈话方面的努力”。介词短语作定语。

更多例句：

He came up with some awkward attempt at conversation. 

他走过来笨嘴拙舌地搭讪了几句。

After some stilted efforts at conversation, he gave up and left. 

在作了一番勉为其难的谈话尝试之后，他不再交谈下去，离开了。

After several attempts at conversation, Moses shyly asked," do you believe marriages are made in heaven?" 

试着开了几次口之后，摩西怯生生地问道“你相信婚姻是上天注定的吗？”

Elizabeth was determined to make no effort at conversation with a woman who was being more than usually rude and disagreeable. 

伊丽莎白觉得这个女人比往常更无礼傲慢，令人讨厌，于是拿定主意，不先开口跟她说话。