Volunteering in a foreign country is potentially dangerous - especially for those who deal with the volunteer and come under the influence of their projects.
A volunteer typically has less experience than a paid worker, but lots of enthusiasm. This enthusiasm needs to be matched by knowledge and humility - the less knowledge, the more humility is needed, but even a well informed volunteer doesn't yet know how little they really know that's relevant, and how much harm can be done with with good intentions.
Rather than going to save or help people, a far healthier approach is to see the experience as cultural exchange in international development, where the volunteer is there to learn, but is also willing to work alongside locals, under their guidance. When there is the opportunity to share possibly useful knowledge, good ways to do that are through questions and in story form, relating one's own experience or learning. Competely avoid "You should..." E.g. a volunteer mgight say "I've see a water filter built like this..." followed by a diagram.