What are the best ways to think of ideas for a startup?

I'm not entirely sure if it's the best, but certainly Are a few I'd do

Stop thinking ! Yes. Contrary to what people think; thinking can be counterproductive. We sapians tend to think so much that overthinking is underrated! Just stop doing it! You know what you are capable of doing and what you’re really good at doing. That's all the information you need to begin.
Throw them self help books away! No offence, but really. Sitting around your house reading about someone who made a million bucks isn't going to get you a single penny!
Quit! Huh, I lost you? Let me explain. Quit your safe full time job that you cling on to so dearly for a better future! There's no better future there, for the most of us. Quit being paranoid about planning, strategy and what nots. Quit being obsessive about your idea thinking it'll always work out. So you fail, dust it up and come up with another strong suit you have. Quit the idea of ideation a start up. Just get going with execution and dive in. All you've got to loose is a not so lucrative job, a horrible boss and a few bucks