The way to get new ideas is to notice anomalies: what seems strange, or missing, or broken? You can see anomalies in everyday life (much of standup comedy is based on this), but the best place to look for them is at the frontiers of knowledge.

Knowledge grows fractally. From a distance its edges look smooth, but when you learn enough to get close to one, you'll notice it's full of gaps. These gaps will seem obvious; it will seem inexplicable that no one has tried x or wondered about y. In the best case, exploring such gaps yields whole new fractal buds.

If you are stuck deciding between two options, you should choose the one that is easier to quit. The option to quit gives you the flexibility you need to successfully react to new information. When it turns out that your initial choice wasn't a good one, don't stick it out simply because you chose it. Just quit.