Richard Feynman seems to have given younger scientists the advice that they should keep a list of a dozen or so of their favorite problems. They should have this list constantly present in their mind. In this way they could relate everything they read or heard to one of the problems on the list and then determine whether the new information could help them in solving the problem.
The claim was: "If you do not work on an important problem, it's unlikely you'll do important work."
I am not a scientist and my problems are not as clearly defined as those of physicists, but I have some definite areas of interest on which I take notes. Every time I notice something that belongs to one of those areas, I take note, enter it into my hyper-textual database and connect it with the stuff that is already in my ConnectedText Projects.