1. Grow. Grow convincingly on your own, without investment. Be confident in your product, know where users come from, in fact know everything about your product and your market (everything), and have a graph that is up and to the right.
2. Network. Go to meetups, clubs, professors, friends, family friends, etc and leverage the fact that you have a "growing" app to make those people EXCITED to introduce you to people with money.
3. When you meet investors, don't go for the hard sell just let them ask questions. Keep updating them as growth milestones (even if it's just every 2 weeks how much you grew) are achieved. Tell them you're raising money early on but that you're not sure when - pick the right moment to say "we're raising" when growth AND # of investors you've met is at peak.
If you're like me when I first started out, you're hearing this and thinking "ok, anybody got any easier ideas? That sounds basically impossible I'm kind of looking for a silver bullet here - I think I deserve it I mean everyone is getting seed money and we're pretty good!".
There's no silver bullet. I'm telling you straight up it doesn't exist, especially if you haven't built something successful before. You have to grind, you have to grow, and you have to network. And it takes time. If you're not ready for that, consider your app a side project and move on.
I hope your venture is successful and be sure to keep the team together and pivot into something else if the current thing doesn't work out... good teams are hard to come by. (The more valuable thing than success is learning what mistakes were made and what move/s would have been better.)
1) http://www.amazon.com/Venture-Deals-Smarter-Lawyer-Capitalis...
I would start reaching out to people in your network (professors, entrepreneurs at your school, executives you may know, anyone who you may have credibility, etc). Set meetings with them, and ask who if they know anyone who many be interested in investing. It's not an easy road, but if they connect you with enough people you may land some investors.
Also, your first investor definitely plays a big role in determining your terms. Don't jump at the first person who offers you money.
Connect with other experienced founders relevant to your industry. Build trust, and they will introduce you to their investors.
Most investors don't respond to cold emails. Introductions from trusted people is the primary source for most investors.
I would recommend you to apply to incubators like Y Combinator and TechStars. They don't require an introduction, they will help you groom and connect you with other investors. Their alumni network is also very helpful, which can open a lot of doors for you.
Even google's terms of financing required a season businessman as a CEO (Eric Schmidt).
Bootstrap or get a founder with business experience. Three CS co-founders makes it even more difficult to raise investor capital, but much easier for finding additional hires.
Look at it from their perspective -- why would they take college students seriously until you can lead with "we have X000 users"?
That said, there's no harm approaching them -- try to get a sense of what would need to change before they'd be sold on investing. Even better if you can get it in writing.
Why do you need investors?
Yes, it's true that many startups get handouts from investors _just because_. That's just nepotism at work. If you have to ask, then you aren't part of that, so you have to make a real case for what you would need money for. It's supposed to be an "investment", after all.