Is it a good approach to ask venture capitalists or angel investors what types of problems they'd like to see solved and right now aren't?

No, it's not a good idea. Every successful or even somewhat successful venture I know of was started either because the entrepreneur had observed and then confirmed a specific pain-point in a market that was unaddressed or that entrepreneur was "scratching their own itch" solving a problem they had themselves that others had as well.

Unless you already count VC's and angels as friends, the idea of trying to get meetings with VCs or angels to ask them what you should build is really a waste of time, as they are unlikely to give you their time.

My best advice beyond what I've written above would be to immerse yourself in the world of startups, best by working for an existing, funded startup. You'll develop a network and a lot of valuable experience about what it takes to take something from idea to product market-fit to a growth-stage company that will be really beneficial to when you evaluate whether you want to run your own journey.

Best of luck!

I completely agree with Tom's suggestions, especially joining an existing startup as it reduces you risk immeasurably, while you learn a great deal.

Beyond that, depending on your background and location, there may be nearby resources to support you.

For instance, if you're looking to focus within the technology space, there may be opportunities to attend a Startup Weekend, 3 Day Startup, or similar event, where you can participate with others to brainstorm and beginning implementation on an idea. While this infrequently leads to a viable product straight away, it frequently leads to meeting potential partners and team members for subsequent projects, and can help you learn to ideate, implement and test your ideas in quickly.

Another possibility would be connecting with local incubators or startup/entrepreneurship support organizations/programs. Regardless of the route you choose, consistently engaging with a community of likeminded in individuals will help you start to see more opportunities and gain a better understanding of the startup process, not to mention connections that can help and support you in the future.

Good luck!

It depends. If you're thinking you're going to walk-in cold to a VC's office, ask them for money and tell them you don't have a business model and want them to suggest something, they're going to get very annoyed and show you the door right away. VCs evaluate hundreds of proposals a day and they don't have time to waste on ideas that haven't even gotten off the ground.

However, if you develop a personal relationship with a good VC, you'll find that they are very happy to advise you in this area. The key is to be very respectful of their time and expertise.

Good luck.

Look at the Lean Start Up model for good milestones associated with each stage of the start up lifecycle.

That will give you a good framework to operate stay focused, and to communicate with your team/stakeholders/investors on what you are working on, what is going well, and where/why challenges have arisen.

No. Focus on what your product or serve can do, not on problems. Most problems are not problems until they become problems. If you asked me what problems I'd like to see solved, I would think, "What? There are already problems? Maybe I made a mistake investing with this company."
Don't stop taking massive action.
Best of Luck,
Michael T. Irvin
michaelirvin.net
My books are available exclusively through Amazon Books. Check out my book "Copywriting Blackbook of Secrets"
Copywriting, Startups, Internet Entrepreneur, Online Marketing, Making Money