Well in relation to business ideas, the more you are exposed to different environments and people the more ideas you'll find. I probably have 3-4 or more ideas a day pop up, but the reality is most wouldn't make a profitable enough business. But I jot them all down and keep them.

Oddly, when I first start developing I had tons of ideas, then I got into the grind of working on some problems and I couldn't seem to think of an idea to save my life. What I realized later is I had gone from asking tons of questions and being super inquisitive to trying to look for ideas. Today, I find ideas because I talk to people all the time, online, in person etc and I like to ask questions and learn what issues they have. What this has done is I can come up with all types of ideas and at some point potential solutions. Then the key is just what might be worth doing.