Morning,
There are only two things I'd have done differently during the 9+ years I've been marketing online.
1.) Not gotten complacent. My first product back in 1998 was magnificently profitable...until the rest of the niche caught on. If I had stayed alert, I would have turned on a dime before I actually had to. In other words, one should not have an ego when dealing with one's business.
2.) Incorporated optins on every single page I built. I created 100s of portals on bunches of niches that generated tons of traffic...just think what kinds of lists I would have today if I had offered an optin newsletter!
One thing Google has taught me...one cannot rely upon
SEO for continued profits. Adwords folk recently got slammed, "thin" affiliates pages in the past months started searching for the Titanic, etc.etc.etc. heck, even eBay will be implementing an increase in their fees in the near future!
Being proactive and not falling prey to complacency is key.
A data point,
Barbara