Over 90% of successful tech companies are financed in pretty much the same way: You start off with basic funds from your personal saving or friends and family investors, then angel investors and angel funds, followed by either venture Capital, or public venture capital. Factoring business invoices is another option, though not unique to start ups. Some new funding opportunities are also developing in crowd funding.
Most startups fold up or better still fail just after the first year. If you are able to survive your first year and are lucky enough to break even, chances are that you could secure some form of investor funding if you work hard and are really interested in external funding. The diagram below is a typical financing cycle for a startup company.