How do I go about seeking capital/investment to develop/build a sustainable farm

To be honest, it always starts with you.

Write a business plan, not so much for the sake of investors (although you'll need it if you decide you want to raise money) but because it helps you clarify in your own mind what it is you want to achieve, what resources you have, and what you need to learn or understand about what you're proposing to do. The process of writing a plan will very quickly reveal the flaws, shortcomings, and impracticalities of your ideas and give you a clearer sense of how to fix them.

Prospective investors want to see that you have actual "skin in the game", so the fact you're willing to put up a significant amount of capital shows that you have faith in your own plan enough to take real risk.

You should ALWAYS use a business entity (LLC or corporation) to separate your personal assets from those of the business and to protect yourself from potential losses and liability.

It's a good idea to have a lawyer involved to the extent that some boilerplate agreements people use might not adequately address your state's requirements, and any loopholes could easily be exploited by clever people. That being said, there are some services out there on the web (can't mention names since we're not supposed to do endorsements!) that do an admirable job of giving you a good starting point which makes it easier (and cheaper) to have an attorney review and amend.

If you have family and friends, that's normally the best and easiest starting point for raising capital, as long as you're realistic with them about the prospects for success or failure. Nothing ruins a relationship like feeling as though you were deceived into giving the other person money.

Make sure you have done all of your legal homework - know and comply with all of your state's requirements for forming a legal business entity. File an incorporation or other organizational documents, obtain an EIN (employer identification number) from the IRS so you can use it to open bank accounts, obtain business credit, and so on.

If you're starting a farm, I suggest checking with your state's agriculture department about programs they have for subsidies, loans, grants, and other programs which can help you bootstrap your project or put you in contact with other agencies or organizations which can give you guidance and help. The same applies to the U.S. Department of Agriculture and your local farm bureau.

Here's an unorthodox idea - why not post a Craigslist ad giving a brief explanation of what you're thinking of doing and ask anyone who might be interested in helping out with advice or labor to get in touch with you?

Believe it or not, it's also a great source of fundraising - I posted an ad for a new business venture and within three days raised $20k from people who thought what I was doing was a great idea.

Educate yourself on what it takes to be a farmer/businessman.

This is a good starting point, but there is much more you should learn before proceeding. I hope you'll take this and build on it, but I commend you for wanting to take the plunge.

Good luck!