You know what helps (me)? Coming from the start with knowledge the success rate is about 10%. Some may say such "negative thinking" dooms your endeavour from the start. I disagree. One can be really committed and still know in the back of your head it is most likely to fail.

This mindset not only means you'll not put your last savings into a venture that is very likely to fail, but also that you remain sane.

Also, sometimes one just needs a break. If you can, take a year off. If you have to work to support yourself, try to take it easy.