Steganography is an interesting aspect of data hiding art where the secret data is embedded in a cover media without raising any suspicion about the existence of that data. Over the years, different steganography techniques for digital images have been presented to be applied in different applications such as security and privacy control. Some of these techniques are based on transforming the image from the spatial domain to the transform domain as a pre-processing step before embedding the secret data. This paper presents an improved steganography technique in the transform domain based on studying the effect of changing two major factors on the performance of steganography techniques. The paper illustrates the algorithms that have been implemented for the study purposes. The results of this study proved that the two major factors that can affect the performance of the steganography technique are the transform type and the data embedding method. According to this study an improved steganography technique is presented based on Slantlet transform (SLT) and a new data embedding method. The experimental results proved the efficiency of the proposed technique in comparison with a previous SLT-based steganography technique.