Choosing the best business ideas will depend a lot on your situation and the type of business you want to start. If you know nothing about restaurants it is probably not a good idea to write a business plan for a vast chain.
Maybe you are looking for home based business ideas or internet business ideas? Figure out the general area of commerce that you would like to go into and then start doing research. Consider your options and evaluate your means. After the a careful research process you can easily separate the good ideas from the bad ones.