I can be too verbose with some of my posts. This will be quick.
I recommend that you read this. It is the Exploratory Testing Dynamics document, a tightly condensed list of useful testing heuristics authored by three of the most thoughtful and experienced software testers alive today: James Bach, Michael Bolton, and Jon Bach. Using it will help you improve your software testing capabilities. http://www.satisfice.com/blog/wp-content/uploads/2009/10/et-dynamics22.pdf
Told you it'd be brief. Go. Now. Read.