Two of the most critical factors in a strong personal brand are visibility and credibility and they both have to be present to have a brand that people recognize and respect.
Is there something that your company desperately needs but does not have the capacity or resources to take on right now? Can you become the champion for this?
As you start to build your knowledge and expertise look to offer a presentation on the subject to inform your department. Then look to spread the message to other departments and before you know it you become the company wide expert in it.
Also do not miss the opportunity to let others outside the company know what you are doing (keeping in mind proprietary information) – but look to associations and professional organizations and conferences to get recognized. That way you are building the company brand and reputation as well as your own externally – but in a very positive way.