So to start off with, you need to verify that your med school is recognized by AAMC. If not, forget it.
Then, you will plan to take USMLE step 1, 2 and preferably step 3 before or right after you graduate. This usually takes two to three years of extensive study before you get ready to take the steps.
If you are a residency applicant in USA who is more than 3 years old of a graduate, your chances to get a match go down pretty drastically. And hence, you must be done with USMLE steps before graduating or right after graduating from the med school. The fresher of a graduate you are, the better your chances to match in the residency program.
Not a bad idea of you start looking into right now. Taking Kaplan courses help.
However, a very high USMLE steps score (which is a must) hardly increases your chances of getting a residency match. Everyone in the applicant pool will have mind boggling scores.
Two other factors that play a vital role are, your immigrant status. If you are moving here as an immigrant on a green card, then that's good for you.
Another factor is U.S., experience.
This is something you must try to get.
And the way to do is reach out to your medical school and see if they have an affiliation with an American Hospital where you can do a couple of rotations?
If not, there is some possibility that you can actually buy a rotation or two in United States. There are some agencies who could help you secure a rotation in a U.S., hospital. The cost is around US$10,000.00
Remember, there are four basic (unadvertised) tiers on the residency match list.
First preference is obviously given to American graduates.
Second, Caribbean graduates who are U.S., citizens.
Third, Foreign graduates (non-Caribbean) with a green card or U.S., passport
Fourth, Foreign graduates with J1 or H1 visa.
Also, have some realistic expectations. Top level specialties usually only take American Graduates.
For example, you will probably be wasting time and money if you apply into a residency program like, Urology, Radiation Oncology, Ophthalmology etc.
You wanna focus on Internal medicine, Family Medicine, and perhaps Anesthesiology or paeds.
Also, there are some indications that Radiologists may have a very poor future in the U.S., since it has started to get heavily out sourced to India.
So perhaps you wanna stay away from Radiology.
This is just a general outline.
You can also join student doctor network forum to find more info.
All the best!