EDUCATION

using a process of adjusting methods, eliminating errors, until the correct answer, method, solution is found

Unfortunately, most people learn about towing trailers by trial and error, which can prove to be a very expensive way of doing things.  BNCI

Young children nearly always put puzzles together by trial and error, `;trying out'; each piece against another until it fits.  BNCI

 Looking at the objects available is of little help, as it's only by trial and error that the problem can be solved.  BNCI