Most Helpful Guy
There's really no easy, simple answer, but you have to get out of your comfort zone and spend time in public places where you'll have a chance to naturally interact with girls.
See if there are any local clubs in your town that you might enjoy. Get a ride to a local hangout and just enjoy yourself and you'll attract someone.
In my experience Tinder isn't very effective. It's better to meet someone in person first and make a good impression by having fun in front of them. You just need to find somewhere with other 18 year olds near you.