This guide offers a comprehensive handbook to scientific research methodology and experimental design, specifically for novice MA and PhD researchers in Education and Language Learning (TESOL/TEFL). It establishes scientific research as a systematic, objective inquiry focused on identifying cause-and-effect relationships through empirical data. The discussion covers fundamental research goals--description, prediction, and explanation--and differentiates between basic and applied research. Key elements of the scientific method are detailed, including observation, hypothesis formulation, experimentation, and rigorous data analysis. Various experimental designs are explored, from true experiments with random assignment (e.g., pretest-posttest control group, factorial designs) to quasi-experimental and single-subject designs, alongside crucial control techniques like blinding and standardization. The article emphasizes the strengths of experimental design, such as high internal validity, reproducibility, and its foundational role in evidence-based practice. It also acknowledges limitations, including potential artificiality, ethical considerations, and practical constraints. Practical guidelines are provided for planning, ethical compliance, test design and administration, data management, and statistical analysis using tools like SPSS. Finally, it outlines the standard APA-compliant structure for reporting experimental research, underscoring the importance of clear, precise, and transparent communication of findings.