Don't forget it. Make the other party your partner. Let them know that your consider them trustworthy and capable for any duties you might refer to them. Make sure that they know they are important to the project and that they feel valued. Be sincere and not syrupy.
Folks can spot a phoney a mile away.
Make instructions simple ,clear and concise -A complicated set of instructions brings apprehension and anxiety. Try a bullet list. Be open to questions - You are only one person and you are not the authority on everything. Have the healthy attitude that there is no such thing as a stupid question. If others are afraid you will go ballistic when asked a question ,you wont get the best results from your helpers.