Your resume is well-written and matches the job ad for key-words and tone. You are getting interviews but you are not pulling the second interview. Maybe your image needs a little cleaning up.
Open a new window to Google.com and search your handle or your name. This is for science, not narcissisum. Are there at least ten items related to you? If not, you need to make sure you make about twenty well-reasoned, sensible comment posts at news sites on articles related to things you wish to be professionally associated. Do at least one a week after the first few and always make sure you are kind, have a sense of humor and seem reasonable. Potential employers look at your Internet presence to short-cut getting to know you.
There. That is the first easy group.
The second easy group is already doing this. You already know that the Internet is forever, and stuff you posted when you were 16 is still around somewhere. You also have spent time thinking about who you wish people to think you are. You already know that putting your best foot forward means not displaying yourself in a bad light. Consider the Wayback Machine, this is a site that archives old stuff on the Internet, so you can waste an hour looking at the style your favorite web site was sporting in 1992. You can also find earlier versions of yourself.
Now, for the rest of the folks reading this, you are going to have a little image work to do. Start with the way you wish to be perceived by your target employer. If you wish to be known as an expert in some field, look at what they are doing, and in your own way, show the similar history that you have shared.
Display only what you wish everybody, including your mom and all your old friends, to know about you. Go through and delete the stuff that doesn't portray you in this light. Thus, all the beer-bong pictures and extremely rude pictures on your Facebook timelines and such should be removed. Absolutely stop having ad-hominem rants anywhere. If you have nothing good to say, say nothing. Find places where you have something good, and of substance, to say.
Luckily for us all, the average person attempting to find out about you will not go too many pages into the Google results, so some of your youthful indiscretions that you cannot expunge quietly will become less noticeable as time goes on.
Your Internet presence is really an extension of your public, not private life. You really need to make sure you have vetted yourself well, so there is nothing objectionable to a potential or even current employer. Remember the six degrees of separation between us all. There are only six people between you and somebody you are trying to impress.