If you are interested to learn more about VCs or you aspire to become a VC, then you should look at the list of required readings for aspiring VCs.
I find it very useful. It also led me to encountering more blogs written by prominent VCs and the associated people in the industry.
So far, I’ve seen a couple of VCs (including USV), which develop an investment thesis as part of their process in determining the sector/market they want to enter. Unless you want to become like 500 Startups then maybe you don’t need to go down that road.
I am starting to develop my own investment thesis which I will share with you once I have a clearer abstract.