How does Montresor describe Fortunato's strengths and weaknesses early in the story?
Early in the story, Montresor describes Fortunato as someone "to be respected and even feared [...]." Fortunato takes a great deal of pride in the fact that he is a connoisseur of wine, and he apparently does have some skill in this area. Montresor says that, like most Italians, Fortunato's knowledge in the subjects of painting and gemmary is nonexistent; however, he is truly "sincere" in terms of his expertise in wine. On the other hand, Fortunato is also very proud, and Montresor claims that this pride is his weakness. In fact, it is Fortunato's pride that Montresor plans to exploit in order to exact revenge on Fortunato for the many injuries that Montresor feels Fortunato has inflicted upon him. Therefore, in terms of strengths, Fortunato is respectable, even intimidating, and he is skillful in regards to wine. In terms of weaknesses, he is proud to a fault, and he lacks skill in other areas.
There is not a lot of information about Fortunato's character in the story. Poe tells us that he is a man "to be respected and even feared," but it is also clear that he is a bit of a bully and enjoys bragging about himself at the expense of others, even though the exact nature of his insult to Montresor is not known. His biggest strength, and weakness, is his love of wine. Not only does Fortunato pride himself on his knowledge of fine wine, but he enjoys drinking wine -- when we meet him, he is dressed in "motley," or the costume of a jester, and already a little drunk. This can be understood as an ironic comment on his fate: it's only at the end of the story, when he realizes that he is being walled up in a crypt, that he realizes that his "expertise" about wine and his vanity have cost him his life.