I would go back and collect email lists and build a solid subscriber list to actively maintain. I was always good with SEO but not email marketing. I just overlooked it for far too long. I would also learn better web design skills 
@luminous88 224350 wrote:
i think the best way to learn is by learning by the mistakes of others, so I pose this question to all of you, whether an operator, affiliate, seo, whatever. I think that we can all contribute, and also learn from the mistakes of others to become better at what we do by sharing our thoughts as well
Knowing what you know today, if you had to start over in your business, what would you do differently?
I hope everyone can contribute something! Please share your thoughts, lessons, failures, etc. so we can all do things better