This is a site you should not really miss for all matters that relate to a start-up project.
https://miteship.zendesk.com/hc/en-us
Besides many other relevant topics, you can browse here for
1) Product development
2) Product design
3) Business model and pricing
4) Marketing and sales
5) Basics of finance
6) Raising money (crowdfunding, equity, prizes, accelerators and other non-dilutive financings)
and many many other relevant and interesting topics.
YOU SHOULD NOT REALLY MISS THIS ONE!!!