This book features the most up to date research results obtained by making improvement in both the sample design stage and estimation stage for the estimation of unknown population parameter like population mean. This book has seven chapters each focusing on the improved estimation of the unknown population parameters in various situations. This book is a part of my dissertation work done at Department of Statistics, University of Lucknow, India as a Junior/Senior Research Fellow. This book will be helpful to graduate students, researchers, applied statisticians and decision makers working in the area of Survey Sampling to appreciate how both sample design and estimation can improve the resulting sampling strategy.