You are right. Finding irony and foreshadowing in this novel is kind of rough. First, a brief overview. John Grisham's novel The Appeal is set in Mississippi. A large chemical firm is being sued by a small law firm for producing and distributing cancer causing chemicals in the community. It is important for the chemical company to win the appeal, as not winning could set a dangerous precedent in further legal cases levied against them. The larger chemical company absolutely pulls out all the stops in order to stymie the smaller company, even going so far as to accuse and investigate the two main lawyers of the opposing side (the Paytons). Obviously, the larger company wants to win this appeal!
The novel is concerned with the political maneuvering of large and small scale elections. The Mississippi Supreme Court is divided in its decision about the chemical companies' liability in the distribution of cancer-causing agents.
In Washington, money arrives through a myriad of strange and nebulous conduits. Often those taking it have only a vague idea of where it's coming from; often they have no clue. In most democracies, the transference of so much cash would be considered outright corruption, but in Washington the corruption has been legalized.
An example of foreshadowing would be the choice of the candidate, Fisk, by the large chemical company to be elected by the people of Mississippi. However, the company is relying on the idea that most of the voting population of Mississippi is unaware that their judicial officers are elected and not appointed.
When Fisk is elected, as expected, he sides with the large chemical company. Ironically, Fisk is directly affected when his son is hurt by a product from a large corporation. However, his desire to stay in the political arena and appear consistent do not allow him to side with the small law firm representing those affected by the pollutants.
Therefore, as you can see, this is a very good example of both irony and foreshadowing. The company, so very sure of itself, has its pride and its weakness, even in the hiring of Fisk. The evidence of this foreshadowing presents itself in the presentation and the development of the irony. Fisk has already been affected, indirectly, by the cancer causing agents of the company in question. Further, I finished an answer about the themes of this novel not long ago. I placed the url in the links below in order to help you further.