first you required to give your 100% in class XII .  Your subjects should be PCM with Computers/IT.  English is must.  Now its time to choose the Universities and your stream in Engineering.  There are lots of reputed universities in abroad so your choice depends upon the sources and your capability. you need to clear various exams. After XII these are GRE, TOFEL, IELTS and if any other is required by the University.  You need to prepare yourself well before.  Meet the deadlines.  Prepare a chart of dates, prepare your self and rest is ..............best of luck.