The sources for financial assistance for international students in America and Canada are limited. Competition for financial assistance is fierce. It is much easier to get admission that to secure financial assistance.
Academic performance (grades) and performance on the entrance exam are the critical ingredients for securing financial assistance. Research and teaching assistantships are the only choices in America for international students for adequate financial assistance.
Research assistantships are the only source of financial assistance in Canada for international students. Unlike America, research assistantships in Canada do not carry tuition waiver and, thus, are not adequate for survival. You are, however, able to augment the income from a research assistantship with ad hoc employment in teaching support.
The student visa in America allows international students to work as a research or teaching assistant, or as an hourly-wage employee on campus. These activities in Canada, however, are considered a form of employment. Thus, you are required to obtain a work permit, in addition to your student visa, from Canadian immigration authorities to engage in such activities.
Do not assume that you will get the financial assistance after arriving in America or Canada. Ensure that you can fulfill all your financial needs before leaving India.