Inspectors, a good "ice-breaker" with the contractor's personnel that you have not worked with before is to catch them in the moment of good work performance. For example, you have an Operator working ROW, walk up to the person, make contact, introduce and identify yourself, and tell them you need to point something out to them. Then tell them that's the best ROW you have seen in a long time. Point out areas of good work such as the soils being separated, no topsoil outside of the stakes, etc. and throw in a tidbit on the importance of the work he or she has done. Let them know how much you appreciate their diligence and talent. Hand them your business card and let them know if they get jammed up somewhere to feel free to call you. This approach can be used with any of the contractor's personnel you are working with and can include a correction you see that needs to be made. Typically, you would start your conversation with the good observations that you see and then ask if they would make a small correction or request that they keep in mind for the future a slight correction that you have observed. And remember to use words that indicate you are part of his team. Such as, "We need to make sure that we do __________ next time." Using the word "we" will minimize the person from becoming defensive.
Keep in mind the philosophy of how you would want to be communicated to and treated by others. Nobody likes someone talking down to them or in a raised voice with vulgar language. Being courteous and respectful can go a long way in building rapport and acquiring a good working relationship.