For step-by-step help with your business plan go here:
http://www.smallbusinessstartup.biz/plan/

For start up costs you will need to include either rent with security deposit (1 - 3 months), build out costs, decorating (eveything from table cloths to carpet and wallpaper), advertising, signage, insurance, permits, professional fees (attorney, accountant, decorator), furniture (tables, chairs, etc), office equipment, kitchen equipment. I'm sure I'm missing other items, but that is a good starting point.

Good luck!