Deciding on which ideas to pursue (sameernoorani.com)

I agree with finding a mentor.

Finding the right mentor takes time but is worth it.

Read Hamming's famous talk on how to decide what to work on. He wrote it for research scientists but the same logic applies: http://www.cs.virginia.edu/~robins/YouAndYourResearch.html

(The talk is entitled "You and Your Research" so if this site I liked to gets overloaded, just search for that).