First of all, you shouldn't worry so much about relationships. You may be lonely, which is understandable, but you should focus on more important things. That may be why you aren't finding the right guy for you yet. You may be dwelling on the need for a romance so much that you are searching for it. Love will come when it does. My best advice for you is to not be so in need for a relationship. It's not the most important thing in life!
Next, I'd say don't settle. Only go out on dates with a boy if you think you could like him. If you continue to go on dates with these losers, you'll just be even more unhappy! You seem like a sweet person so don't just settle for anyone.
Try to imagine what the perfect guy is like because no one is perfect. You just need to find someone who will forget all your imperfections and one that you can forget their imperfections. So, try not expect everything to go perfectly. But, put yourself out there more. Be confident in who you are and have fun. Try new things and meet new people!
Good luck!