Product photography really requires a studio, studio strobes and big softboxes to get the look that is favored in contemporary product imaging. I've done a lot of it, mainly in Santa Fe, but I have the equipment and would set up in the client's places of business, doing it on location. If you do have the studio lighting equipment, you do not need a studio if clients are cool with letting you set up in their place for the time needed to do the work.
As sepiareverb said, small stuff is easier to light. You'll want some rolls of background paper to give a solid seamless background. White or black is good for most things, but ask the client.
Big stuff is a lot harder because of the difficulty of having a proper background, plus it takes more powerful strobes and larger softboxes to light it evenly.
The REALLY hard part is finding clients. I have never, ever gotten work by calling or visiting businesses and asking for work. Ever. The only way you'll get work, and other commercial photographers who are more experienced than I am told me the same thing, is by word of mouth from people who know your work and who themselves are well connected.
The stuff I show above was done in Santa Fe. The small items were for a business whose owner had a friend hire me to teach her photoshop. The student's friend hired me to photograph products for her website and when she found out that I knew how to design websites, she asked me to maintain hers because the guy she hired to build it ran off to Mexico before finishing it.
The photo of the Uber Press was one of a number I did for that company over a week. The owner of the company was given my number by the woman whose website I designed. I could go on and on like that, its how I have gotten all my commercial photo work. Start talking to people, tell EVERYONE you know that you do commercial photography. Someone will know someone and will mention your name.
Learn to do other stuff. I do photography, graphic design, and web design. Its hard to get enough business today doing just one thing to make a living. I taught myself web design and learned php and coldfusion as well as normal HTML and CSS.
Some business cards that I have designed.
Another area of photography you might look at is photographing artwork for artists. Its something I have done a lot of in Fort Wayne. Artists need photos of paintings, drawings, and sculptures for their websites, to submit to galleries, and some want high-resolution images to do giclee prints from.
