I need to know the top 10-20 effective online marketing tips for a
retail watch business online.

http://www.asktog.com/columns/062top10ReasonsToNotShop.html

http://www.paulgraham.com/articles.html
  Especially the submarine article - but read it all.

that link doesn't really help much.

Well here are tips that would apply to any on-line retail business.

1. Understand SEO start hanging out at webmasterworld.com
2. Understand SEM and conversion tracking- you need the tolls to
measure your conversions.
3. Get a good stats package for your server
4. Study the other most succesful sites in your sector
5. Understand link building and how it helps
6. Use any and all tools available to you to try qualified real people
to your website.
7. Have a quality website, design wise and shopping cart wise
8. Employ unique marketing tactics such as the ones at http://www.adimpact.com
9. Read, Read, Read.