You just gotta practice and find your grip while draging and how you put your hand while draging, your way to do it, not other people ways. Its been 1 and a half year i drag click and i started drag clicking good 1 week in.
As darcedstone said, practice is key. Also, I recommend against using tape of any sort if you have a roccat or bloody mouse as it permanently ruins the texture if you use tape for a while. Have a marvelous day!