Do extensive market research to find out about the clothing business. Look into how other brands became successful, and use the information to come up with a business strategy. Find out what your competition is doing in terms of pricing, variety and promotion.
Find a niche in the market to create T-shirts that appeal to your target audience. Ensure that you provide high-quality products.
Consider the cost of labeling, printing, bagging and hand tagging among other expenses. Come up with a reasonable budget, and find ways to finance your business. Meet with investors, or consider taking out a bank loan.
Promote your business on the Internet to reach a wide audience. Give away free samples to attract potential clients. Create an effective marketing campaign to promote your products.
Find partners, and collaborate with other businesses to increase your chances of success. Work with people who have intimate knowledge of, and experience in, the clothing industry.
Set weekly or monthly goals and keep track of your progress. Evaluate your business strategy periodically to change what is not working.