I thought I would share the first step in this process with you, in case you find getting a summer job as daunting as I do.
Obtain an Application
And either fill it out in the store (or wherever you're applying) or ask if you can take it home and bring it back later.
Before you leave your house to go application-searching, make sure that you do three things:
Put on appropriate clothes that make you feel confident. Granted, you're probably not going to have an interview on the day that you fill out an application, and a lot of times you'll never set eye on your future boss -- somebody at the front desk might just hand you an application and ask you to fill it out. But you never know who might see you and it's best to make a good impression on your future boss and coworkers.
Think about where you want to apply, so that you'll have a strategic plan when you leave your house (although you can always be flexible and apply to different places that you see while you're out). If you're applying to a lot of businesses, make sure to have a list of all the applications that you've obtained, and note whether or not you've turned them in yet so that you won't have any surprises or confusion later on. On a related note, if you have a lot of applications you might want to write where they came from in pencil, since some applications don't have the business' name on them and you wouldn't want to mix them up.
Smile, since people will be more likely to hand you an application if they feel that you're approachable and friendly.
At first I was intimidated about asking for job applications, but it's actually a lot easier than I expected. I obtained applications by looking for businesses that looked like they might hire summer help. I walked into the store (etc.) and approached the person at the front desk/checkout (making sure to smile and be generally pleasant!). I asked them if (insert business name) would be hiring any summer help this year. They either responded... yes, no, or "maybe but it's not likely." If there was a possibility of being hired, they would hand me an application and I told them that I was going to take it home to fill it out and bring it back shortly.
Then you just fill the application out, which is generally self-explanatory (or if things are getting complicated, ask Google. ;) ) Don't forget to bring the applications back and ask where to turn it in. Somebody will either direct you to the manager or take the application for you. Then you wait. If you want you could follow up to make sure that the application has been received by the appropriate person.
Step one: accomplished.
P.S. Remember to say thank you to the people who take the time to provide you with a job application. But you already knew that.