Most entrepreneurs do not think of investors as people. Instead, they think of investors as money - a fatal error.
Private investing is not like picking a stock on NASDAQ. Private investing is personal. Investors have goals, preferences, fears, and problems, just like entrepreneurs. When cut, they bleed. When things go wrong, they worry. So, the relationship you build with investors is essential to obtaining money from them.
In the most simple terms, investors can be put into two categories: Subjective and Objective.
Subjective describes an investor who is some how emotionally connected to the entrepreneur or the company and its product or offering. They know the entrepreneur directly or through a third party so they have a comfort level regarding the entrepreneur's ability to perform. Or they are familiar with the product or more specifically the need for the product and wish they had thought of it or could have bought one a year ago. Typically, these investors get involved at a very early stage, may be even in the "friends and family" round. They may be accredited, but they may not. Because of the emotional connection, they are more forgiving of missing elements to the business plan or business model. They want to invest and look for reasons to invest, to justify their emotional decision.
An Objective investor is in the business of investing. Because they are likely to have many projects they are considering investing in, they look for reasons not to invest. For example, if they are considering 5 projects and trying to make a decision, they have to eliminate at least 3 to narrow down their choices. Therefore, they look for things that incomplete. The business plan is difficult to read or understand is the easiest factor to use. The financial projections are unrealistic or incomplete because they use some standard formula rather than real data, so the investor knows that entrepreneur is just "guessing". The other big cause for elimination by an Objective investor is that the company has an inadequate plan for execution once the money is received. Their use of funds is vague and they haven't completely figured out what they will do with the money. An Objective investor doesn't want their money used to "figure stuff out", they want it to go directly to activities that will help the company scale and generate revenue, and can be measured through milestones or project plans.
Ultimately, it will be an emotional decision for the Investor to actually write the check. If you are seeking serious investor money, you won't get to the point where the investor can make the decision to invest if you have flaws in your business plan or business model.