A resume is more about stability and clarity of skills (working, speaking, etc) than just a history of your working experiences, if that is all your potential employer wanted then he'd ask you to fill out a canned application instead of bringing in a resume.
In my former life I managed a rather large telecommunications company. During my tenure I hired and terminated many people and probably read more than 2,000 resumes. One thing I looked for was someones ability to communicate. So instead of saying something like "I help others with their bikes" use "friends and family usually rely on me for their routine bike maintenance". <-- just my two cents
Anyhow, you are young and this employer knows it so they won't expect much as far as a previous work history. But they would be impressed to see that you have been involved with your local church, clubs, school, etc. Anything that shows you have innitiative and the ability to stick to something.
A new employers biggest fear and letdown when getting new people is the person that is late, unfriendly, and quits shortly after being hired so they do read between the lines and look for stability.

So just keep my input in mind please.
* Calrity on your resume is a must. After all, you will be doing customer service and if you don't know how to write legibley, how can you be expected to help out conversatively?
* Don't lie. Not only is it illegal in most places to lie on a resume but chances are your employer will find out in the future. And if he does, do you think he can trust you not to rip him off if the first thing you ever did was lie to him?
* A few days after dropping off the resume call back to see if it has been reviewed. You can always use the line that you are not sure if the contact information was correct or you have been busy and might have missed the call but do call back after a few days just to show your interest. The employer will take note of this.
* After the interview, thank the employer. Trust me on this one. I hired a person once because he sent me an email a day later that only said thanks for your time in 10 words or less.

good luck with this too, sounds like a great job for a young person