Begin by studying the work of the masters and by practicing with your camera in diverse settings. Focus on understanding light and form, and emulate the compositions and vantage points of the professionals.  Sadly, few, if any, academic programs will adequately prepare you for a career in architectural photography.  Instead, strive to get the most well-rounded education possible, and then find an established photographer whom you can assist and who is willing to mentor you.  Also, a solid business education is as important to your success as your photography education.

A sharp wide-angle lens, a sturdy tripod, and a camera with a large sensor and high dynamic range are key. Quality over quantity is paramount.  Tilt-shift lenses are the next logical step in progressing as an architectural photographer.  Many architectural projects can be shot without auxiliary lighting, thereby helping the beginning photographer economize.  Eventually, you'll want to invest in auxiliary lighting and additional lens choices.

Build a strong portfolio, then actively network within the architecture and design communities (AIA, SMPS, ASID, etc.), and utilize online platforms (LinkedIn, Instagram) to showcase your work.  Don't overlook the importance of making in-person contact.  A portfolio containing a few exceptional images is far more valuable than a large collection of mediocre ones.

A compelling image balances technical skill with artistic vision, conveying a sense of scale, atmosphere, and the building's unique character.  Vertical lines must be parallel, and exposure and color balance must be spot-on.  Standing in a corner with your widest lens is rarely the best choice!  A great architectural photographer always asks the question, "What's the story we're trying to tell?"  Successful architectural photographs always answer that question in a unique and compelling way.

Research industry standards, consider your experience and the project scope, and provide clear quotations to potential clients.  When in doubt, find a veteran photographer who is willing to offer advice as a mentor to get you started.