Supporting

Savvy investors can not only be a great source of financing, they can also be a great source of information when starting a new business.  Angel investors often look to take on a role in the new business, and this usually is realized in the form of a coach or mentor.  Having the perspective of and investors and a third party, in general, is a great way to make sure you are on the right track.
Sometimes they are the voice of reason when a reality check is needed.

These are the roles an investor/advisor can offer you support:

Strategic Planning – You may have a great idea or a great product but no definitive direction to take it; this is where having an advisor can absolutely help.  An advisor can offer much-needed clarity by helping with the creation of mission, goals, and objectives.    

Business Plan – For some entrepreneurs, this may be their first attempt at writing a business plan.  For the investor/mentor, this may be the hundredth business plan they have been presented.  A mentor can help guide the entrepreneur in making a solid business plan in line with what would be investors are looking for.

Business Negotiations – Not all entrepreneurs have the experience or confidence needed to negotiate with well-seasoned investors.  An advisor can assist in lending the entrepreneur the investors perspective.  This can at least help the business owner know what the person on the other side of the table is looking for in finalizing a deal.  Having insight on these variables can help facilitate the entrepreneur’s presentation.

References:

Amis, A. & Stevenson, H. (2001). Winning Angels: The 7 Fundamentals of Early Stage Investing. Great Britain: Pearson Education.