hey!

if you want to be accepted at a top university, you should make relationships with a few professors there first. Ask them intelligent questions by mail or email. Read their papers.

The simple fact is that you need to stand out from the stack of applicants. Talking to professors at your current university who are alumni at the university you are interested in is good too. Do projects for them. Offer to grade papers. This is called networking. And will help you in securing admissions into your Phd