Take a day off. Go do something fun. For me it would be to take my daughter to the park or something, go shopping, and just make a day of it. Clear your head and feel life.
Come back the next day and write down on good ole' paper what you have done in the past. Strategies, sites, keywords, ect. You need to lay everything out and find a similarity between them. When you establish what this is, don't do it in the future
No, really. I have people I have worked with. Since they are trying to make money off the internet they kept trying over and over and over to compete with the "make money online" niche. If this is you, then stop right there. You need to give up on that niche because only the strong survive. Sure some get lucky or think outside of the box and make their establishment, but for most it is a losing battle.
If you are ONLY targeting make money online/work from home... then stop it right now!
As one mentioned, check out Google trends, YouTube. Hell, watch TV and pay attention to commercials. You need to find what people like and are interested in. I don't care if it is a niche I know nothing about, if I can find keywords that get searched but there is no competition, then I jump right in.