"Yet it remains difficult to round these Angel investors up. "The process of getting angel money is, in my observation, a little bit like herding cats," he said. "It's a confederation of 12 to 15 wealthy individuals who are doing this somewhere between a hobby and a part-time activity." Angel investors tend to travel frequently and miss meetings, or have trouble following up. "This is a great group to go after, but it can take awhile. You can't go in there and have a half-hour meeting over breakfast and they write you a check. That happened in the bubble phase, but not now. To get eight of them to all write checks requires many, many meetings."

Companies should take on more than one source of funding, he said, adding that he likes to co-invest in new companies with other venture capitalists to provide additional "brain power." "You should try to take a round (of financing) with three venture funds together so that when you hit a problem - and you will hit a problem - you don't have just one decision-maker." He suggested that when building a syndicate of investors, companies should look for venture funds that have worked successfully together in the past. Greene also warned that venture capitalists will be as just as involved in a firm they take a 15% stake in as they would with a 50% investment."