You may want to choose a brand with a history. The brands covered in these books should be good candidates.
Encyclopedia of Global Brands
Encyclopedia of Major Marketing Campaigns
Encyclopedia of Major Marketing Strategies
Brand Failures: The Truth About the 100 Biggest Branding Mistakes of All Time
Rankings & Ratings
Finding your brand on one of the many brand ranking projects should be useful.
Interbrand Best Retail Brands 2014
Corebrand Corporate Branding Index
BrandZ Top 100
Forbes World's Most Valuable Brands
American Consumer Satisfaction Index
Business Rankings Annual (not just brands)
Ranking The Brands
Market Research Reports
Market research reports offer one stop shopping for may of the topics you need to cover in the brand audit such as sales, marketing trends, competitive environment, and consumer survey results. If you don't see a market research report for your brand's category ask me for assistance as some reports are in specialized databases or difficult to find in general business databases.
Passport (Euromonitor International)
Covers global consumer categories. Search by brand keyword or expand industries categories. Avoid the brand search on the landing page as it leads to brand share statistics without context.
Cannot search by brand but by broad category. Coverage for consumer products and services in the U.S. with limited international.
Provides marketing reports for many industries in the U.S. Some reports may be too dated for use.
You will need to search business news and academic research about your brand. These are the best points of access for both the practical and the scholarly.
Offers information on global advertising and marketing trends including case studies, articles, reports, opinion pieces, and expenditure data. (Previous title: World Advertising Research Center)
Business Source Premier (EBSCO)
Provides access to a wide range of academic business journals and trade magazines. Topics include management, marketing, accounting, finance, economics, international business, operations management and management information systems. Full-text access may be embargoed for up to three years. Coverage goes back to 1965.
ABI/INFORM Complete (ProQuest)
Provides access to scholarly journals, dissertations, working papers, key business and economics periodicals, and country-and industry-focused reports.
Advertising Age Datacenter (AdAge)
Find out how your brand fares on the web and social media platforms.
Social Bakers Get analytics on facebook, YouTube & Twitter presence by brand
Alexa Get web analytics
Quantcast Get web analytics
SimilarWeb Get web analytics
App Annie Get app analytics
Offers data and reports related to digital marketing. Topics include advertising spending, digital marketing, social media, media usage, e-commerce, e-mail marketing, and device usage. Coverage is global.
This and that
MRI University Internet Reporter
Market Share Reporter Find market share calculations published in trade news, market research reports and by trade associaitons.
Ad$Summary Reports for brand spending by media type
TESS (U.S. Trademark and Electronic Search) Find out who owns brand's trademarks.
Find out about the advertising agencies that make brands.
Global New Products Database (Mintel)
Find out about new global consumer product brands