How long does it usually take for your brand new niche affiliate sites to start making money from sells from that particular niche?
Depends on how you're generating traffic. If PPC, then a couple minutes to an hour. If SEO, a lot longer.
It really depends on the program. Sometimes you will never make a cent. What programs are you wondering about?
depends on the competition, your method of advertising, your product quality, your price, etc. that's too vague a question to be answered.
Very vague questions... sometimes you've already built a site with traffic and then add an affiliate campaign; it's only minutes. Other times you take the long term SEO strategy; hoping for a solid pagerank. I've experienced a "traffic flood" and the "Google Sandbox;" it all just depends on the niche, your writing quality, content, traffic, age of the blog or site and much more. best of luck to you.