Referrals

I have been contacted by recruiters from 4-5 companies on LinkedIn, so far. I am actively looking for a job. But I have not been contacted by companies like Uber, Dropbox, Credit Karma, etc. I do not have any friends working there to refer me or on LinkedIn. I know that simply applying to jobs on their portal is not enough. In what other ways can I get their attention and get to call me? I need more calls because I am not sure I will go through all of them and also need to practice them before I give the Google or FB interviews. I have not interviewed a lot before I joined Microsoft on graduating. Also, it's not bad to give many interviews.