Interpreters should truly love Jesus and be committed to Him. This is a ministry, not some sort of occupational, educational or social work. The end goal is not to just provide an interpreted service, but a true ministry. Dedicate your heart first, and then God will use your hands.
Have the right motive. Why are you interpreting? Are you motivated due to selfish reasons? Looking at our motives may be uncomfortable, but critical. Deaf ministry needs us to keep our motives in check.