A good precaution would be to not get cut
Here's what I can remember from my microbiology class in vet school. Some may not apply 100% to people and, of course, your doctor will know better so talk to him when you go on the hoist for your yearly maintenence.
Tetnus is an obligate anaerobe bacteria so puntures are worse than cuts because it seals off the oxygen. I've been told to try and get it to bleed to flush it out and wash the wound thoroughly. Antiseptics right off the bat are a good thing. Keeping up to date with your tetnus shots is the big one though since it is the tetnus toxin that causes the problems, not the bacteria themselves. The vaccine is protective against the toxin itself and that's how it helps. By the time you see the symtoms, the toxin is in your blood and antibiotics may, if they kill the bacteria by breaking down the cell membrane, increase the amount toxin in the bloodstream. If you are on immunosuppressive drugs, your immunity is lower which is how the vaccine.
My advice would be to make sure the doctor knows that you are a blacksmith and work with rusty metal so they can help you protect yourself and what early warning signs would be so you can get in for early treatment. It's amazing how many people just assume the doctor will know how to protect you and diagnose illnesses without knowing these predisposing risk factors.