Just my thoughts when looking at an idea or person:
Any investor will want to know what is in it for them firstly, return on investment, your abilities, ie any experience in a similar venture or staff required to complete the business successfully. IE do you have them??
They would want/prefer to see a well laid out business plan to show you are thinking clearly and taking the business seriously.
Try to imagine someone you do not know asks you to bank roll their idea, what would you ask and expect?
If the business plan looks great, all the surveys and great product mean nothing if you have no faith in the person, and so forth. Know your figures and be clear what your target market and business will be, and as importantly where you want to see it go, and where you realistically believe it can reach over say three years.
A lot of people make the mistake of pitching what they think people want to hear, canny investors expect things to cost a bit to start, so do not say you need £20k year one investment if in reality you believe you need £30k.
Trust comes top of many investors priorities, try and pitch a slanted view and you will be dropped like a hot coal.
See Dragons Den for extra tuition and advice
Lastly something many people in your position should take the right way, if anybody is wary or unwilling to lend to you, there could be a very good reason. Take their comments on board and re-analyse your plans, they might be saving you a lot of heart ache in the long run, as well as themselves.
I'm sure more experienced guys can give some better advice.