Order of the parameters in the request
When building the GET request pay attention to the order of the params, the same order might be kept when generating the signature otherwise the signature logic wont work.
Order of the process while generating the signature
The process of creating the signature is important, follow the step by step guide to make sure each step is done correctly otherwise the signature would be wrong.
URL encoding values
The client might input special characters and for that we need to be sure to URL encode the values but only during the generation of the string and not in the signature creation process since we are encoding all of the signature at a later stage.