These Notes summarize a series of practical issues deriving from the experience of supervising Diploma Thesis conducted mainly at the Department of Transportation Planning and Engineering at the School of Civil Engineering at NTUA during the past decade. The notes aim to provide the student with a series of encoded and practical ways of dealing with the numerous stages of the Diploma Thesis preparation. The notes address the important issues encountered while conducting a Diploma Thesis such as structure of the Thesis phases, literature review and the relevant search tools, the writing of the Diploma Thesis and the presentation.