Most high profile blogs don't mind sending traffic to people with interesting ideas - especially up-and-coming bloggers. After all, you did provide them with free content. But, if your guest post is simply a rehashed old point, it's dead in the water. Here's what some high profile sites may look for:

• Original content that tells their readers something new. This is simply the most important factor of all.
• Posts that are backed up by research, charts, data, and expert quotes, not your opinion. It's easy to write what you think. It's much harder to produce data that backs up an argument.
• Substantive discussion. Short posts usually get rejected. When you're coming up with ideas, ask yourself: "So what?" and "What's the point of the post?"
• I highly, highly, highly recommend you read this post by Ramit Sethi on writing guest posts for high traffic bloggers.