[sometimes]

If you haven't applied, apply.

Research the company on the web. Have a word with their HR people and ask them if you can have a chat with somebody on how the company works as an organisation.
Sometimes there's a 'job contact', see if you can get a meeting.
Your prime 'task' is to get to interview. From there everything is positive. Go to the interview, get the job - done deal.
Go to the interview, don't the job - approach the company and ask them for feedback, most larger orgs ought to do this, is part of the 'people' thing they do now. It's not going to help you for this job, but feedback will be able to do some proper reflection based on other people's perceptions not yours. At the end of the day you have to sell yourself to them. If they ask you a bunch of questions related to 'non-skill' subjects. like aspirations, good and bad experiences, etc. which you weren't prepared for, you can be prepared next time.
Go to the interview, don't get the job - you didn't get this job, i know a fair number of people who have been offered alternative positions, or, when another job comes up and you only just missed, then maybe they'll look more favourably next time.
If you don't get to interview, contact them and ask why not - not in a sort of arsy kind of way, but looking to improve yourself - you never know the candidate they want might take another job.

Sorry if this is all obvious, but it's easy to be defeatest before you start and as a consequence be too humble. Can you imagine trying to interview somebody who thinks the job is going to somebody else....it will.