So: first and foremost don't rely exclusively on online dating. If you do that it's going have a pretty negative impact on your view of the dating world. Online dating sucks ass, even when you're good at it.
As for "how to deal with it" you need to see it for what it is: a revolving door. Your first priority should be securing as many dates as possible as quickly as possible. Long, ongoing conversations will almost always end up going nowhere. Assume half of those dates are not even going to show up and consider yourself lucky if even one in 4 that you do have an actual date with are anything beyond outright boring. When I'm dating hardcore I will schedule 2-3 dates over the course of a weekend and most weekends that ends up being 1, maybe 2 actual dates.
I'm assuming if you're looking for personality you're using a platform that has profiles, and if you're not then you should be. Don't let the people who met the love of their life on Tinder fool you, it is not the place to look for personality or anything beyond a hook-up. I personally like OkCupid, but there's all kinds of 'em out there that may be better depending on what you're looking for. Aim for profiles that are actually filled out and have some information, and though this may seem obvious only message the people who are interesting and might be compatible. Looks are important, but if you're looking for someone to date long-term you also need deeper compatibility than that. Anyone with only a few sentences in their profile is an immediate pass - that's the easiest indication that they are not taking it seriously and likely just want attention.
When it comes to the date I usually go for a quiet bar & grill type of joint that has drinks and decent-but-cheap food. Since you're under 21 maybe do coffee? The idea is a place where you can have a conversation that is pretty chill. Expect that the majority of your dates are going to want you to take the lead. This might be a little different with chicks dating chicks but I doubt it. If no one takes the lead the date is boring and goes nowhere, and she's probably walking away thinking you have the personality of a cardboard box in the same way you're thinking that about her.
You'll probably know by the end of the first date if the person is worth spending any more time on, if they're not then say "fuck it" and move on. If you're not sure give 'em another date. If you're still not sure about whether or not you should schedule another one then they're not worth the time, say "Fuck it" and move on. Again: revolving door - you're going for numbers, kid. The more you can get in and out the sooner you'll stumble across one that's worth keeping around.
I've been doing online dating for about 10 years, and that's the easiest way to summarize how I've learned to go about it. It's become much more tolerable.