Admission to Stanford,Harvard, MIT

According to my experts :
1.All require GRE subject Test. Some claim that it is not needed but in order that your application stands out I recommend you take GRE subject Test. This will facilitate a decision in your favor.
2.They need some research work. Preferably published individually or jointly with a professor. You may even have some peer reviews. People plan this well in advance and somehow wriggle through and get their name inserted along with a professor.
3.Your field of interest should match with a professor willing to accept you as a graduate scholar.
4.Excellent Recommendations written by Professors / Superiors knowing you well and willing to write specifically about your reseach interest and scholarship. These should not be vague or general.
5.Outstanding Essays. Each School should be provided an essay specifically written for it and should not be a ‘copy-paste’ exercise.
6.Excellent GPA
7.Good GRE and TOEFL scores
8. Apply early.
9. Above all plan early about the steps required to be taken. Succesful people start taking the initial steps from Junior year. Do not wait till the Senior year.
All or some of these come to play to decide on your application.

If you are admitted by these institutes than financing your education will not be a problem.
An important observation
Admission in PhD is difficult as compared to admits to MS degree.
Universities generally require good academics and/or good research experience. If you have these you can get into a very high rank university. It is believed that good research experience can lead you to a top 1-20 ranked university.But this does not imply that academics and subject test is not given due weightage.
As you go to low rank universities (21-40) they concentrate more on academics and subject tests.Universities Ranked 41 and below concentrate on academics and experience but not subject test.
But once you get admits 80-90% of the times you get assistantships.
Academics play an important role if you don’t have experience.

A more Important Note

I am well aware that every applicant will not meet each of the criteria listed above.However if you cover about 80-90% of these you have a fair chance of admission and you must try. You may be lucky.GOOD LUCK