What do you know about your target customers? The web design information 
about your target customers can help you in to develop your product to 
better match  what your customers want. Who is your target market?  This 
can help you work out how best to reach your customers with promotion.

For niche marketing you need to know who will buy from you and in what 
quantity. Ask who is my perfect customer? Does your product cater 
specifically to women? Is it more useful to one industry than another? 
Does your product go logically with another type of product?  If you find 
lots of competition in your marketplace then you will have to create 
unique niche marketing in order to position your business against them.
 
Do something that you know something about - something that you like 
and enjoy.

Demographics are the basic measurements of web design. Things like income, 
employment, industry, age, gender, family status and location will 
probably describe the customer who buys from your industry. 

You can't do too much financial modeling - if it works on paper, then 
maybe it will work in practise - but if you can't get it to work on paper, 
then it won't work. Much better to find this out on paper than by losing 
money.  It is very important to find out if there is a real need for your 
idea before you have invested too much money and effort. 

Be clear about what you can invest in the business - both in money and in 
time - be very careful about borrowing until there are clear,  quantifiable 
results happening.  Be realistic about financial goals. 

The way to build your website traffic is to build a website that gives good 
value to your visitors.  Make it into a popular site so visitors will want 
to come and others want to link their sites to yours.