As the Internet allows easy access to almost every written materials, the rate of plagiarism in educational institution has become one of the main concerns shared among teachers at all levels. This paper is based on the studies the researcher done from 2010-2015 focusing on plagiarism at undergraduate and postgraduate levels. The research involved 65 Master’s Degree students, 31 PhD. students and 44 Undergraduate students in three universities in Northern Thailand. The research instruments included questionnaires, in-depth interviews, pre/posttests and essay writing. The research procedures included the experiment employing class activities, a blogging project and eLearning lessons. The findings reveal that digital technology made it easy to plagiarize. The results indicate that more than half of the participants failed to understand and to address the concept of authorship in using outside sources in their writing. Most of the students (82%) were unaware of plagiarism and did it unintentionally. The essay evaluation pointed out that students could improve their writing by using eLearning lessons and feedback from peers and the instructors. Class activities and discussion sessions on the target issues were effective tools and witting in supporting students to write with plagiarism awareness and to use outside sources more carefully. The analysis of essays written by the participants revealed that students plagiarized as they were not confident in their English, laziness, and lack of knowledge on plagiarism. The author will discuss on strategies in detecting plagiarism in students’ work. The highlight will be made on how to assist students in using digital texts as sources for writing wisely.