For any product you need to understand the various market segments that exist for that product. Then you need to focus your limited time and money on the (largest) segments that bring you the fastest revenue, with the lowest cost at maximum profitability. It's no different when selling stock as an entrepreneur. The market is the investor community, and the main segments include Family and Friends, Individual Angels, Angel Groups, and VC firms.
The stage of your company, your markets, your type of company, and the amount of money you need will dictate the best segment (investor) to approach to optimize your time and chances of successfully raising money. For example, if you need $50K it is not a VC deal but more likely a deal for Family and Friends, or Individual Investors. If the amount is $500K, then focus on Angel Groups, and if $5MM or greater, it's VCs. Amounts between $2MM and $5MM can be tough; too large for Angel Group, and too small for most VCs. So the real key is how much you need and for what -- the real business milestones we discussed previously.