For some reasons, even though I websites has pretty great onsite SEO I thinks, my Twitter profile "outrank" personal site consistently in Google/Bing SERPs on different computer around country and different search engine accounts..… I can not overcome this. Advice?
Your website needs more content, or more relevant content. I have a site in 1st place, Amazon is in 2nd (same product) and twitter is lower down in the top 10. You need to be adding more content that's relevant and getting links will help.