5. Trying to get by with a "Brochure" Site.
If your site to be the top ranking site in your Business Domain, then you have to deserve it. The best way to deserve this status is to offer a good amount of relevant quality content, easy navigability and a pleasing look. You cannot get by with just putting a few pages with general descriptions about your company and service offerings and be done with it. For example, if you are selling perfumes, then back up your offering with reviews and helpful information for the consumers. In case of Electronics Items, information about after-sales support always helps. This will make your site a valuable resource. Lastly, try to have a web form. This makes a handy lead generation tool for you and at the same time makes it convenient for users to contact you. Human visitors, and search engines alike, will soon recognize you as an authoritative source of information in your field.
6. Redesigning an Existing Site and Neglecting the Old URLs.
Your old website may have been unimpressive lookwise, but maybe it had traffic flow and search engines may have cached those pages and people are finding those pages based on the information that the search engine bots compiled from them. If you redesign your site, and completely toss out the old urls, without compensating for it, then you are tossing away all the traffic you had built up earlier, because search engines will be sending people to pages that no longer exist.
There is a way to avoid this. If it is possible, stick to the same structure that your old site had and retain the same urls for the new pages. If this is not possible then make sure you adopt URL redirection. For this you will have to make a .htaccess file (a text file with instructions on the functioning of the site). This file will tell search engines to permanently redirect traffic from an old url to a new url. When this file is in place, anyone typing the old url will lead to the relevant page on the new site. Makes sense?