Don't even bother attempting to meet girls online, dating apps are basically made for girls. Even the "unattractive" ones will get hoardes of horny guys and you will have to try and appease to their highnesses by trying to stand out and humor them. Just look at reddit /r/tinder.
Best way is to meet in social gatherings. The one girl I was completely infatuated with I met at work and she was an intern at the time but I was lucky as well to have a ton of attractive girls where I work.
If you're in school/college, that is obviously one of the best places to form friendships and work towards relationships. You can join social clubs and attend events, you just gotta put yourself out there to enjoy different activities and you'll run into girls. Key thing is to be kind and funny, you don't need to be brimming with confidence although that will help.
I never went to bars/clubs so I can't speak to the success level there. There are also sites like meetup.com where you can find different activities to attend and meet new people, although I heard its usually 75% men mostly there for the same reason to score chicks lol.