A novel algorithm that improves a generalized integer transform based reversible watermarking scheme is proposed in this paper. In our proposed algorithm, two main improvements have been achieved: adaptive thresholding and efficient location map encoding. With adaptive thresholding, suitable threshold t is selected adaptively, which ensures enough embedding capacity for the watermark while keeps the distortion introduced as low as possible. This modification is influential as an unsuitable threshold can lead to insufficient space for the watermark or even degrade the visual quality of the image. Moreover, efficient location map encoding helps in reducing the location map size, which down to 0.4 of the one unmodified in average. Therefore, more capacity is available for embedding as there is lesser overhead information. Overall, it provides more embedding capacity whereas improves the visual quality of the embedded image.