The details about your project:
First, you should start off with designing a LOGO. Work with colour, text and graphics to finalize an idea that is visually interesting and pleasing to the eye… as well as communicates your brand values. Your logo should be at least 1000 x 1000px.
Second, start making your branding materials. All materials should coordinate or match, using the same colours, typefaces, graphic elements and information. Don’t forget to include your business name, personal name, title, website, address, telephone, etc.
FYI: I got all these fancy-pants measurements from the excellent resource: http://designerstoolbox.com/. USE IT!
BUSINESS CARD: Standard business cards are 2 x 3.5″ (300 dpi). This can be horizontal or vertical.
Looking for some inspiration? Check out: http://blogof.francescomugnai.com/2008/05/70-new-amazing-business-sards/, http://www.reencoded.com/2008/05/20/42-awesome-business-card-designs-with-links-to-100s-more/
LETTERHEAD: Standard letterhead is 1 x 8.5″ and sits along the stop of a document. It should have all pertinent business information.
ENVELOPE: Standard envelopes are 8.875 x 3.625.
POSTCARD: Can be either 4 x 6 or 5 x 7.
RACK CARD: 8.5 x 3.625 (vertical)
BLOG HEADER: 800px x 300 px.
Any of the additional promotional materials will be up to you to determine sizes. Like I mentioned above, http://designerstoolbox.com/ is an excellent resource and even has templates for you to choose from.
Remember, this project is due Thursday, January 19th!