Whether you are helping someone remotely or seeking help from a third party, establishing trust is both very important and extremely complicated. You should presume an adversary may have access to all your account details as well as your original communications when seeking help. This adversary has an obvious interest in intercepting your secure communications channel and providing specific, bad advice. Security tools have built-in ways to verify if the person you are talking to is actually the person you think you are talking to. When getting advice, compare it to concepts discussed on well-respected guides such as Security in a Box, resources at Electronic Frontier Foundation and Press Freedom Foundation.
More information on the various technical aspects of trust can be found in the Establishing Trust section.