As sama answered above (below?) Angel investing is likely not going to help your cause. If you are already successful to the point that you have enough financial viability, then it's a lot easier to walk away from something that isn't working. Which is bad for YC. Scrappy founders will work their butt off before hanging it up. That said. Financially successful or not, great founders (2nd time, 3rd time) and a great product/company, is what will likely get you in.