You are absolutely right. There are a lot of people who are making money (some a lot) online.
And, yes, I suppose that they don't tell you everything, but there is a TON of informationabout how to start an online business.
If you have all of the knowledge you say you do, then there is no reason why you should not be making money online. You canmarket any of those skills, or all of them.
Rob mentioned not trying to do them all. I kind of agree, with the exceptionthat I would still market them all, but focus on theONE THING that you feelthat you can do the best, and that you think will be the most helpful to others.
In other words, your main market focus might be SEO. You simply listyour other services with a brief explanation of what you do.
Now, you need a web site (blog), squeeze page (always a good idea to get email addresses),and you need sales copy and a bit ofcontent for your site.
You also need a way to take payments.
Now you need to promote. If you are as good at graphic design, web design,SEO, and Social Networking as you are saying, then this should be a breeze.
Use those SEO skills to grab a high page rank. Grab attention, and bring in visitors, and customers using your Social Networking skills.
It's not about secrets, it's about hard work and focusing on what isimportant. It is up to you to decide what is important.