Where is the error?

I use a fundamental analysis mode to shortlist stocks and then watch them for sometime to get a feel of the range in which they seem to move and then buy in....I seem to manage to get good set of stocks into the watchlist... but then I seem to be going wrong in my execution - while I picked Gujarat NRE coke, IVRCL and RNRL at the right time, I missed out on Crompton Greaves, ICICI and Sesa Goa.

I am trying to understand why I finally execute the trades I do and the ones I dont - still not very sure. The other problem is the target price I have - once I hit 30% return, I get jittery and some how feel like its time to exit, while the stock might be headed higher ( E.g - ACC ) - I need to improve my target pricing, which will hopefully also let me understand the margin of safety on a stock.

I am stuck with a dud currently - Federal Mogul goetze - its more than 45% down from my acquisition price and will do some research and dump it very soon - didnt cut my losses in this stock - I could have done it when I was 25% down but then that figure looked daunting - stupid move - Will post what my thinking was, and why I think I should move out in a different post.

Current on the watchlist - Manugraph, ICICI bank and Vijaya Bank