Sorry for the novel post.. If you are in Canada or the US, get a job in the restaurant business. Not fast food, sit down full service with tipped employees. Start as a host, busser, dishwasher, food runner, whatever. Get your foot into the industry while your young so you have experience and contacts. This will get you tons of experience with customer service and communication, which is essential in many careers but also in day to day life. It will also make it so much easier for you to become a server/bartender if you one day wish. It may be looked down on by some, but IMO is the absolute best way to make quick money in the least amount of time while you further your education, etc. The grunt work you will be doing as a first time worker in a restaurant will be similar to that of any minimum wage job, but will really gives you some potential as a young adult.
I went from absolutely struggling to pay my bills, barley eating & going to school full time while working 32-40 hours a week at my stressful, shitty minimum wage job. I got lucky and was hired as a server/bartender with no experience (which is rare) and my life instantly became so much easier. I started off working only 16 hours a week and was making the same amount as when I was busting my ass full time. I upped it to 24-32 hours a week and was making more than double, while still working less hours. It took so much stress and taught me many skills that I use in my current profession and life. The year after I graduated I worked full time as a server and am actually embarrassed to say I still have yet to make that much in a year in my full time health care profession that I studied 4 years for. It literally blew my mind. So I still do both, because why not?!
Not that all restaurants would allow you to do that well, and it takes a certain type of personality to make the real money. Canada and some states where the minimum wage for tipped employees is still pretty high is the best bang for your buck serving, however I'm sure 95% of servers in both countries make over minimum wage.
Last added bonus- serving/bar tending allows you to meet SO many people! It's a great way for them to become personable with you, which I have found amazing for networking. I actually had a few job offers/interviews set up in my college profession because of people I met and talked to while serving.
Good luck in whatever you do! Good work ethic is the most important thing and will only always benefit you in the end. No matter how shitty the job is, as many first jobs can be, work your hardest and best. It will only set you up to have a good working mind set and open up future opportunities.