You are not doing yourself any favours waiting to apply for a job. If you are interested in the position you need to apply immediately or else you might miss out.
Remember that you have a lot more experience that you think when you are applying for your first role out of school or university.
When preparing for your interview go over your part-time jobs, things you have completed at school, volunteering, babysitting, captaining a team. It shows that you are reliable and a team player.
Can be easier said that done, but try your best not to get discouraged. So few people land the interview when applying for roles, so if your not landing one right off the bat, its not a loss. You need to keep applying for roles and putting yourself out there. You will eventually get there.
There is no need to reinvent the wheel when writing emails. To save yourself time and stress check out the many email template options online.