[aufreak3]

Switching from giving importance to "which idea to pursue?" to "which problem to solve?", can greatly help ... as it did during my phd. Changing from "interesting ideas" to "interesting problems" not only forces you to think about things that have some worth pursuing, but can also give you a clear view of priorities - i.e it is easier to tell the relative importance of problems (at least for me) than of ideas, it is easier to formulate questions that you don't know the answers to and can therefore focus on collecting data about before you begin working on it.

If you have an idea along the way that sounds interesting, just ask yourself "what problem would be solved if I work on this?" ... and pretty soon you'll gain tremendous clarity, often discarding many useless ideas very early on.

This shift has perhaps been the biggest learning of my phd years. Compared to the effect this has on me, I find the "agile methodologies" etc tips relatively useless.