That said, I want to talk about a skill (theory?) I used for job hunting that has always been effective for both me and those I have advised with job searches. That skill is getting inside the head of who you need to be for the proposed job.
I feel that a lot of people who are looking for a promotion or new job display their understanding for that position as they understand it from their current position. That's wrong. It is said that you have to dress for the job you want, not the job you have - it's even more important to think like the job you want rather than the job you have.
To use an example that is familiar to most of us, let's look at a bank teller looking to transition her/his career to a personal banker position. The core skill set for a teller involves, money handling, customer service, detail orientation, and referrals. Those skills are all transferable to a personal banker position, but transferable is the key word.
For example, let's use customer service. A teller provides customer service via a strong greeting, in-transaction conversation, and a strong closing. Their mentality needs to be around answering the customer's primary need and good communication. These are all very reactive actions. A banker, on the other hand, needs to be much more proactive. While addressing the customer's initial need/request the banker also needs use their service skills to deepen the relationship for the future.
These are subtle differences, but the step of using customer service skills to build a relationship rather than a more "one-and-done" mentality is important. If you are the teller, applying for promotion, it's important to understand how you would approach customer service differently to be successful at that next level.
That's just one example, but it is true of almost every job change out there. Just like the clothes, you have to think like the new job.