"First" jobs can be in things like retail, fast food, restaurant, "helper" for construction sites or other skilled trades (roofer helper, plumber helper, etc), car wash, etc. The purpose of a first job is to get some experience to be able to put on an application for a better job. These aren't normally jobs that will pay the bills and allow you to move out on your own, unless you are living with friends.
When you get an interview, remember to be on time, dress appropriately, cover tats and remove piercings (unless you are positive they are ok), don't chew gum. Make eye contact. smile. shake hands. Everyone is nervous at interviews, so, don't worry about that.
Employers are looking for reassurance that you have a good work ethic and have what it takes to do the job. So, let's say you apply for a roofer position and they ask, "have you ever been on a roof?" If you say "no", that might be the end of it. But, if you realize they want to know if you are scared of heights, you could say (if it is true!), "no, but I am not afraid of heights. I go zip lining and bungee jumping."
Do you have transportation? If you hesitate, they will pick up on that. If you will be dropped off and picked up, you can say "Yes." you don't have to explain. However, if you say "yes, and if something goes wrong, I have neighbors who will help me out." Everyone has a car that won't start at some point or another.
They also want someone who helps the company to make or save money. On the job injuries are very costly. So safety, following the rules, not taking shortcuts are all important. The same for regulatory compliance. Suppose you are selling alcohol and fail to check someone's ID and get busted by the alcohol bureau. The company gets fined.
And, ability to get along with people. You should be able to give examples of that from school activities. Sports, clubs, group projects, etc.
Did you do any community service projects? volunteer activities? Remember to work that in as well. Sometimes I include them when the application asks for "experience," unless it specifically asks for "paid" experience.
Before you look for a job take some time to think about what are your strengths, hard and soft skills you have, perhaps ask around your friends/ family about what do they think your strengths are. Write them down and include them in your CV and cover letter as well.
While you are talking about a new job opportunity, your enthusiasm and motivation will be what will distinguish you from other candidates. Make sure you understand very well what the role requires and be prepared to answer why would you like to be part of this team, why this role suits you and how will you contribute to this role.
I wish you all the best of success in your future endeavors and if you find a role where you would like to be very well prepared for the interview let us know.
As a high school graduate there should be numerous entry level type job openings in the marketplace. However, given the current Covid-19 issues, I would keep an eye on your specific market area and the entry level jobs that would be available. Remember, as things loosen up and return to normal, there will be more and more jobs coming back online.
If you are interested in specific area then keep an eye out for those specific opportunities. You can get the names/addresses of companies in those specific areas and send them a cover letter and resume!
Stay positive and stay focused and you will be working before you know it!