Hi @futuremind, thanks so much for taking the time to read my answer and respond. While I may know very little about the collectable trading field, many aspects of running a business are universal. I guess to sumarise my experience, having a dream and fulfilling it is great, but unless you also can apply a critical, calculating view of the situation, you may end up in trouble.
Research lots, take the emotion out of your decision making. Take advice, but make your own decisions, don't just blindly follow the advice. Back your judgement 100%, but never be afraid to admit when you are wrong. Analyse everything - your business, your competition, the market. Do a SWOT on your business - and a proper no-shit SWOT without any emotion attached.
Best of luck with your venture, and thanks again for letting me know you got something out of my answer here.