Expanding on your advice: when diversifying it helps to not throw darts. It may be best to not have investments only in tech, auto, health, etc., but it's quite another to randomly choose a company or two in different sectors.

Unsolicited advice ;-):

* Tech: ARMH over MSFT over FB (phones/tablets need to be low, low power and P/E of FB seems egregious)

* Auto: VLKAY over F over GM (100MPG TDI trumps "made in USA" trumps bankruptcy)

* Health: ILMN (NGS is the next $100BB market http://bit.ly/fYehBI )

(OP: I'd be more than happy to be a "trial run" for your angel investing. ha! ;-)