If you can't make a legitimate claim to some public objective, you're probably wasting your time. Those TV commercials we all see are misleading. Get your story straight: Be able to explain in two sentences why you merit public money. Make it about public benefit.
2. If you do think you can argue for some legitimate public interest, start by doing a good search of federal, state and local grants that might apply to you.
Use business.gov and sba.gov for federal, and state -- local are harder to find, but find them. Ask you local chamber of commerce or Small Business Development Center for help. Some bankers are tuned into this too.
3. Most business assistance comes in the form of low-interest loans rather than straight-out grants. I know, you don't want any loans; but this is the real world now. Be realistic.