Grades: You need good grades and be in the top 5% of your class. If the rest of your profile is extremely strong, you'll probably be fine being in the top 10% too.
Resume: Make sure your Resume looks neat and impressive. Presentation is very important; mention relevant details about your projects or internships. The quality of your work is extremely important rather than quantity.
Letters of Recommendation: This is probably one of the important components of the application. Make sure you get extremely strong recommendations. Strong recommendations can make a huge difference.
GRE Scores: While some people think all their application chances depend on their GRE scores, this is not the case. GRE is only a part of your application, so don't limit yourself if you don't do too well. For UC Berkeley, you're good if you have 163+ in Quant, 154+ in Verbal, and 4+ in AWA. This does not mean you won't get admitted if you score below them.
Work Experience: Working in a reputed international company and getting good records from your boss there would definitely help.
Statement of Purpose: Probably the most important part of your application. UC Berkeley requires an Academic Statement and a Personal Statement. Make sure you spend a lot of time on them. Start as early as possible, as your SOP will never be perfect, and there will always be scope for improvement.
The admission requirements will differ depending on whether you are seeking admission as an in-state, out-of-state, or international applicant.
After meeting the program and GPA requirements, you must take the SAT or ACT exam. You also have to submit Personal Insight Questions for your application. The essays are the only chance the admissions committee has to understand your personality, so take a lot of time on these essays. Letters of Recommendation are probably one of the important components of the application. Make sure you get extremely strong recommendations. Strong recommendations can make a huge difference.
With all that, good luck with your college applications!