I just found some gem articles of Paul Graham and the one on top ideas strikes a chord..
You can’t directly control where your thoughts drift. If you’re controlling them, they’re not drifting. But you can control them indirectly, by controlling what situations you let yourself get into. That has been the lesson for me: be careful what you let become critical to you. Try to get yourself into situations where the most urgent problems are ones you want to think about…
thoughts worth avoiding
…I’ve found there are two types of thoughts especially worth avoiding—thoughts like the Nile Perch in the way they push out more interesting ideas. One I’ve already mentioned: thoughts about money. Getting money is almost by definition an attention sink. The other is disputes. These too are engaging in the wrong way: they have the same velcro-like shape as genuinely interesting ideas, but without the substance. So avoid disputes if you want to get real work done….
top idea in mind
I suspect a lot of people aren’t sure what’s the top idea in their mind at any given time. I’m often mistaken about it. I tend to think it’s the idea I’d want to be the top one, rather than the one that is. But it’s easy to figure this out: just take a shower. What topic do your thoughts keep returning to? If it’s not what you want to be thinking about, you may want to change something.