Eish has some tips for UT:
Take care of all of your reference standards and calibration blocks. Store them in secure containers and keep them preserved from corrosion.
Ensure that all probe and cable connections are secure prior to inspecting.
When working in extremely dirty environments it is a good idea to cover your machine with cling wrap, but not too thickly, otherwise you will have difficulty in seeing the signal responses.
Consult with your client as to what backup or alternative inspections will be effective in confirming an indication that was found.
Always report any limitations encountered during your inspection. Access difficulties, flaking paint and corrosion will prevent you from performing an effective inspection.