The number one thing is to do your research. Is there a market for your idea? How is your idea different from others like it. Although you'd like to think you've come up with something novel, there is almost always competition whether it is direct or indirect. So know your competition and figure out how your product or service stands out from theirs. You can use this as a selling point. Whether you finance the business yourself, get a bank loan, or approach venture capitalists, that comes later. Once you have an idea, knowing how marketable it is and what or who your competitors are and how they are servicing this market you'll be sharing, is the first step.
I own my own business and it didn't cost much to start up and although I had a few competitors, I have many things that make my service a valuable option for clients. And I made a profit in my second year. But, beware, most businesses don't. It depends on the type of business, your expenses, and how fast clients hear about you and make the decision to use your service. And if you have expertise in your particular field and have built a reputation before you strike out on your own, you'll likely already have a following and potential clients.
The first thing I suggest is to look at the following resources. They cost nothing or very little and you'll benefit from expert advice. It will also help you think about not just starting a business but what it takes to survive. Knowing whether or not you are a startup CEO or a CEO that will stay in it for the long term is valuable. And having an exit strategy, even if it's not written in stone is smart.
Here's some resources that helped me. By the way, I launched my business before I did a business plan. If you are asking for money, you need to do a plan and if you are funding it yourself and don't want to do a plan right now, it's ok but eventually you will want to do one. It will help you see where you are and where you are going.
1. Subscription to Entrepreneur Magazine
2. Also check out Business 2.0
3. SCORE.com (you can get free expert advice here, you can take free courses, you can be walked through a business plan, plus all sorts of other information. It can be overwhelming at first but pick the things you really need most and begin there.)
4.Book - Pop! Stand Out in Any Crowd by Sam Horn
5. Book - No B.S. Time Management for Entrepreneurs by Kennedy (It really is no B.S. and a fun read!)
6. Book - Complete Business Plann by Bob Adams (If you prefer a book - it's almost like a book for dummies)
7. Instinct - Tapping Your Entrepreneurial DNA to Achieve Your Business Goals (It's a different way of thinking, it's fun and may open your mind to things you hadn't thought of)
I found having the Entrepreneur magazine subscription of great value because I was constantly being reinforced every month. It kept me in the company of others who were trying to achieve the same things I was and it helped me to keep going when I wanted to quit.
I'm not affiliated with any of these things that I've suggestion. These are just suggestions and they've worked for me. You may find some or all, or you may be led to other things that work for you. But above all, keep your passion. It's the one thing that will keep you going when you feel you have doubtful moments.
I also want to add that you should look for books or mags within your own industry that might be good. Knowing everything that you can about your own field will help you find a niche. Check Amazon.com and browse and make sure to look at the comments on how helpful or not helpful the books were so that you can make a more informed decision and put your money to good use.