How do I prevent arthritis in my fingers?

No smoking. Osteoarthritis (oa) is generally not preventable except to avoid trauma such as boxing, karate, etc. Typing will not cause oa. For rheumatoid arthritis (ra), the best way to reduce your chances of RA is do not smoke.
Arthritis. There are different types of arthritis the two most common being osteoarthritis and then rheumatoid. These are very distinct entities and are treated quite differently. For osteoarthritis which is largely a mechanical issue with cartilage erosion you can be careful how you use your joints. For rheumatoid there are other guidelines. Speak with your doctor, a rheumatologist, or hand surgeon.