I tried online dating a long time ago (2004 or thereabouts, long before mobile apps) and found it tough going. Some girls just seemed to want to chat, send pics etc but kept finding excuses not to meet. Others there was just no chemistry in chat, and I appreciate that's a two-way street and I was a bit naive / poor 'chat up game' etc. I think part of the issue was they are probably talking to a dozen other guys at the same time and you never know where in the pecking order you stand, they might want to string you along as a 'backup' option, just like the attention or whatever. So my advice is try to meet up pretty quickly no matter how cute / good a match you think they are. I think I wasted about six weeks talking to one girl before giving up. One I met much more quickly, we didn't click but at least I knew and could move on.
I think you also have to take a decision on whether you want to go with a scattergun approach (contact lots of women with very little effort for each one) or something that is more tailored (commenting on specific things in their profile etc). The latter might appeal to a certain type of girl but is probably wasted effort in many cases.
Obviously times have changed now and the stigma is gone, I imagine for many younger people online dating is probably viewed almost as the 'default' route for finding a partner.