1. How my site looks like?

2. Whether my contents can pull the viewers to my site?

3. What is the current trend in market?

4. Whether my domain name suits my business?

5. How many pages can I create in my site?

6. How can I inform my friends to visit my site?

7. How do I earn from my site?

Once the site is built and runs for few days other questions start coming to mind

1. How to get ranking in google?

2. What is my overall Alexa Ranks? How many sites are above me?

3. What keywords are important to get to the top ranks in search engine?

4. Whether my pages are HTML and CSS valid or not.

5. How to keep track of my customers?

6. Where should I advertise my sites? and so on so forth..

Now what to do next....

1. First thing you should know is what the viewers actually want?

2. What is unique in your site that other site doesnt have?

3. How fast your site is opening compared to others?

4. How well you have organised your contents? And whether they are indexed by search engines or not.

5. What keywords you have used that can pull your customers?

6. To which search engines you have submitted your sites? Google, Yahoo etc

7. In Which Directory your site is listed? Like dmoz.org, Yahoo.com, etc

8. How often you use the social community Sites like facebook, Hi5, orkut, twitter etc?. If not than register today

9. You have to take out your precious time to get your site to the top ranks.

Now for a regular diagnosis you can visit the below mentioned links to check your website statistics. Everything you can get in there. Numerous SEo tools to help you out.

1. Joomla SEO Tips

2. Website Sellers

These sites will give you insight of SEO or Search Engine Optimisation.

All the best to all Webmasters.