Before the first deployment of new website you add Google Analytics tracking code on it and want to search engines start to indexing it. Of course you don't want to have any errors on first indexing. My experience shows that one's of important files that search engines trying to get are robots.txt and favicon.ico. First tells robots about possible restrictions, second - just an icon of website (which is shows in address bar of browser).

About robots.txt you can read on For ASP .NET websites most of all uses:

User-agent: *
Allow: /

User-agent: *
Disallow: /*.axd$

First two lines tells robots that they can crawl and index all content of website, second two lines tells crawlers not to index files with extension .axd (which are resources files).

For favicon I recommend to use Favicon.ico Generator. It's free, not require installation any software on your computer, allow you to create icon online and it's very easy in use.

Another powerful software (but it is application and shareware) is Axialis IconWorkshop.

Don't forget to put these two small files to the root of your website next time. ;)