The time line.
No matter if you have the "hot" product, that everybody in the market wants right now, or if you are selling a "non-trend-product": Do not expect your business to start up like a rocket. Starting an online business is a slow process, unless you have enough financial backing to start with a huge campaign.
If you work part time on your page, I would consider this a realistic time line:
Week 1: you got the idea and think about it
Week 2: investigations on the product and who can do a web page for you
Week 3: Prep-work for setting up the page
Week 3-5: Web site programming, finding a web host, registering a domain
Week 5-6: Finding a PSP, Test launch (maybe without the shop)
Week 6-8: Beta test of page, finishing the framework and shop, looking for Ad's and link pages.
Week 10: Official launch
Week 45: The first sale.
What I'm saying here is: Nobody is waiting for your page to launch, and it will be a while before you make your first sale. It is a total buzz to launch a new page, to actually go there, type in the URL for the first time and finally see "out there" what you have been working on for weeks. The only trouble is: That buzz is just for you, and maybe your family, and looking at your counters and stats will be a slight disappointment in the beginning, because you realize: "Nobody was waiting for me to open this page."