I'm not an expert in television animation. However, my vague knowledge gathered over the years combined with knowing how and why investors invest leads me to the following conclusions (this advice goes for film as well).
Business Plan
If you are approaching individual investors or investor groups or any source of money other than a studio or producer, it is very likely you'll need a business plan. While I cannot say that this is always the case, it would suck to be in a situation where you meet this investor who is interested in your idea only to have to tell him that a wait is required while you put one together. Be prepared. If you don't ever need to use it, then fine. However, if you are serious about doing such an endeavor that requires so much money, the cost of a BP is a small price to pay. If you are pounding the pavement trying to find money sources, there is nothing sweeter than having a BP with you that you can just slap down in front of them. Wealthy people or companies do not waste time. If you don't have what they need, they will simply move on to the next investment. There are no shortages of people who need their money. Don't lose the opportunity.
Here are some common questions I get:
Q: Can we hire you to write a business plan?
A: The short answer is no. I'm trying to remain anonymous with this blog and if I start doing work like this, I will be spilling the beans. Besides, my wife keeps telling me I don't spend enough time with her as is.
Q: There are people on the internet that I can hire to write a business plan. Should I do that?
A: That is a possibility. Although a business plan for a film or television show is a little different from a BP that sells your average widget. With enough research, these people can educate themselves to write a good one. However, I personally wouldn't take the chance. Get someone that knows the business. If they take the time to learn what's involved, they are just going to have to charge you that much more for their education. There are also people that claim to have knowledge in the film industry and write film specific business plans. This is closer to what you want, however, again, animation is a specialized subset of film and you may want someone that has knowledge in this specific area. Maybe it could be a combination of one of these "Film Business Plan" writers and an animation business consultant that can check over their work. However, I have the feeling that these BP writers use a template and just slap new numbers in for each client.
Visuals
The next important attribute to include in your pitch to investors is artwork. The more the better. You really need to spend some money in this area if you can afford to. Many investors won't consider dumping money into your project if they don't see that you have done the same. And I don't just mean man hours, I mean - they want to know that you have invested quite a bit of your own money into the idea. Artwork is a good way to do this. Employ someone to do character designs, some background artwork, etc. Eye candy goes a long way. If the final product will be CG, try to include actual finished CG character artwork. At the very least, have someone draw the characters to immitate what the CG will look like (shadows, shading, etc).
If you can afford it, animation tests would be icing. If you can burn some DVDs and include them in the package, you are going to get more attention. Investors want to get an idea of what the final product will be like. However, this is not necessary and the cost is often prohibitive.
Presentation
Finally, you need to package all of this together nicely. You should have both a CD version that can be loaded onto a computer and a hard copy for those old timers. Put the plan in a nice three ring binder at the very least. If you really want to impress, have it bound. The artwork should be printed with no scaling artifacts. I've seen some pretty ugly packages in my time, it never amazes me that people do not take the time to make sure the artwork is reproduced well. Another idea that I've seen implemented well is putting artwork into the BP. It spruces it up and breaks up the pages and pages of text. It also ensures that it will be seen by everyone who reads the plan. Finally, put all of this together in some sort of nice folder with your contact information clearly visible.
This post is only my opinion of course. I've seen projects get financed that are ugly as sin. However, I think that your chances are increased if you take the time and effort to do these things.