Research:
Having a few abstracts/manuscripts in your CV definitey wil make it stand out, as not many IMGs have that. Even an active project without an abstract is better than having nothing. There are few research labs and scientists in every country. They can be approached and any opportunity, whether big or small, should be jumped upon. US funds research big time and many US scientists are looking for hard working people to work for them. This provides an excellent avenue for IMGs.
Decide upon a stream which excites you, because research can be painstaking and one needs to be particularly excited about the area, otherwise sooner or later, the energy levels will go down.
Talk to scientists in that area in your own country. Email as many scientists in various US universities. Prepare a good cover letter and CV highlighting your enthusiasm. Once again, this may take months to mature. But perseverance pays. Usually, the target should be 100 emails per day and continue until you get an approval letter!
US Clinical Experience:
USCE is almost a necessity these days to get into a good residency program. It refers to any clinical exposure to the US healthcare system.
USCE can be divided into:
1. Observerships: (Or 'Shadowing')
Easier to get, and usually cheaper than the rest. If you secure one, you usually tag along with a physician and observe whatever he does. You are not allowed to touch a patient and hence this type of USCE is considered inferior to the rest. But something is better than nothing.
2. Clerkships: (Or 'Electives')
Harder to get and usually costlier. Costs range from $100 - 2000 a month usually. Here you can actually do all the duties that are expected of a final year medical student in the US. You need to be in final year of your medical school, called internship in some countries. Means the final year of your medical school before you get a medical degree (though the term 'internship' in US refers to first year of residency). They are very highly rated by the program directors and really help your CV to stand out. There are some universities which offer free clerkships if you have cleared TOEFL, an English language test.
3. Externships:
Very hard to get and very costly. Can cost upto $2000 a week! Same as clerkships, except that people who have already graduated from medical school can apply to these.
Every aspirant these days has some USCE on his/her CV, so you should try to get some before applying. Giving your CS exam on the same trip as your USCE/research experience may save you valuable dollars against airplane tickets.
Professional Societies:
Membership of a few professional medical societies can also be considered. Societies related to your field of interest can be searched on Google and then a few can be joined. Atleast one US society should be joined. The costs for one year membership usually range between $25-100.
Languages:
Some programs who cater predominantly to minority populations, like some programs in eastern states, prefer candidates who have knowledge of languages other than English. Spanish and French languages are probably the best bet. Spanish even more so, due to large Hispanic population all over the US.
Extracurriculars:
This is one area people frequently mismanage. Either they highlight it too much or pay no heed to it. If projected in the correct way, they can help people remember you and your candidature. You can assure yourself one question about an interesting hobby of yours during every interview. The goal is to be a little understated in this regard, but also preventing the interview to go too monotonous or boring. A light discussion on this can also relieve some stress during the interview. Never ever lie about anything. Interviewers are smart enough to figure out any lies, so as far as possible, always carry proofs like certificates.