1- Be clear with the motive for building the site.
Answer few basic questions.
a. Do I just need online presenceb.
b. I want to actively push content through my site
c. I want to sell products online.
2- Once you are clear with what you want to do , search for similar ideas and get few reference for your site.
3- Think about the way you want customer to behave on your site. Draw rough flow chart for the activities you want your site visitor to do.
5- Pictures for your site- Collect all the pictures you have related to your business. Depending upon the site you have thought, try getting references from the internet. This will speed up the process of designing as your requirement can be Cleary communicated