Web和移动客户端Web服务技术的建议

I have set up a LAMP server on aws. I am planning to create a web service with both a web client and an android client. I am not exactly sure where to start. I would like to create a RESTful service but have no experience with it and don't know where to start. I have hit restful services for the android app that I have created but have not designed one myself. I have worked with Java and RoR. I would like to learn Python as well if required. Any suggestions would be great.I have set up a LAMP server on aws. I am planni