Just to add to what Jacob has already said, think about commercial issues facing that company as well. Are they likely to grow in size, are there many opportunities in the industry that they can take advantage of, how would the law firm be able to offer its services to help it in these business opportunities. You could also look into who the client you've chosen currently use for representation (which firms make up its legal panel) and consider how the firm you're applying to is better placed to meet the client's needs. Also think about the client's international strategy, what level of support it would need globally and how your firm can meet that!