It's all about self confidence, what you bring to the table, and selling yourself.
Online dating is convenient but it's not "Pussy-Mart' where you just select what you want and wait to fuck! The people on the other end are real threat and blood, looking for love. Learn what you have to offer, present it in an attractive "non asshole" way. Genuinely get to know someone when you respond. I guarantee I could take your information and get you some replies without lying.
The bigger problem is that females on dating websites get roughly 11 billion responses every seven seconds. You have to make yourself stand out by saying things and doing things that others wouldn't. Don't say "You're beautiful" or "Your eyes are _____". They hear that every ten seconds.