The first and the foremeost source of capital for a business is your own funds - your savings or those of your spouse / family members. The benefit here is that repayment terms are comfortable and no interst is usually payable.
Second source is your credit card. But I'd advise to go slow on this, as the rate of interst would be high and penalties for defaulting also high.
Thirdly, you could touch your friends for some.
Fourth, your prospective customers can be a good source of capital, if you can convince them to pay you in advance. If you are able to do this, nothing like it. Think about it. For this make your product so attractive and your reputation impeccable.
Fifth source is the bank. It is banks' business to lend to businesses of various sizes. Their rates of interest are also reasonable. They do however need some kind of security -- personal guarantees, third party guarantees, mortgages or pledges.
Sixth source is your suppliers. Get supplies on credit.
Seventh source is a letter of credit opened in your favour by your supplier.
Then there are VC funds.
And also the capital market.
Have I missed any source?
Today, David, happens to be my birthday. So you can consider this as my small birthday present to you! All the best!
-- R C Kathale