Fill the information about you under the ->Settings -> Customize Profile*to know the people who you are and what you are interested in.Choose the topics you are like or interested in under the*Settings - > Manage Interests.
Manage your profile photo of yourself under*Settings -> Profile...
As everyone discussed above, Google Webmaster is good tool to fix URL errors or even broken links.
Other tools
ISUP.me – Lets you know instantly if your site is down for everyone, or just on your end.
Web-Sniffer.net – shows you the current HTTP(s) request and response header.