[quote=@Dinh AaronMk]
<Snipped quote by BrobyDDark>

Look presentable, return again and again. If you can: turn in your application directly to the boss or whoever reviews them (manager, whatever).

If you can too then I'd keep a dummy application on hand with relevant past employment details if any. That way you can easily copy down contact information for references when/if you got any. Not all apps will be the same, but most will have similar details.

And if/when it comes to resume do not be my brother and under "awards and acknowledgement" put "Always on time", "Good worker", and other useless shit.
[/quote]

Be careful though. Handing in applications was (at least in the US) already going out of style back when I first started looking for jobs in '06, but now that process is pretty much extinct. The jobs that still do that seem to be those sort of tiny businesses that mostly hire friends and family anyway, so if anything hand-delivered applications are sort of a red flag. 

Anyway, my advice. 

Work out a resume, even if you haven't ever held a paid job. Fill it with extracurricular activities, grades, shit you've done as a hobby that you think might be relevant to working, whatever. Of course, you don't want to say "I was in charge of a Guild in WoW" or something like that, but if you do [i]anything[/i] that would impress a vapid middle aged HR manager, stick it on there. If you are a teenager you might not really use a resume, but making one will give you an understanding of how to present yourself professionally. 

As for clothing, don't go all out or you will look like a silly fuck. Wear business casual for anything that isn't professional level. People who wear suits to McDonalds interviews tend to look uncomfortable and awkward, so don't do that. 

And read the fuck up on interview questions. Seriously. The shittier the job is, the more over-the-top their questions will be. This is where I really struggled when I was fifteen. You do not want to freeze up when asked something like 'What are three words that describe you?'. The key to interviews (though I can't say I great at these, but still...) is to be confident and comfortable.