When you go to pick a hosting account for your website, if you intend to get search engine results do not use a shared IP account. Get a hosting package that provides a unique IP for your domain.
Not only do you avoid being blocked by corporate firewalls because someone else sharing the same IP is a porn site, you also get a quicker trust factor from the search engines. Trust is important because until you are trusted, you remain low in the rankings no matter what you do.
Another piece of advice to build your domain's trust: always make sure your registration has over a year before it expires. Google thinks spammers are cheap and lazy - only registering domains for a year and on shared IP accounts.
