Pick a programming language. One language. Python is a good choice, but there are many other good choices. Then do some tutorials in that language. When you get stuck, ask (here) for help with what you ran up against. Be sure to show what work you have done.
While griswolf's advice is spot on, I would like to add few more details to help you out.
Broadly speaking, there are two types of "web services"; RESTful services and SOAP based ones. I would recommend skipping over SOAP services because they are enterprisey, complicated and "not so hot" these days. ;)
A lot of online services these days offer REST API which makes it a perfect choice if you want to play around. Depending on the platform you are on, I would recommend you to install the "requests" module for Python, which makes it dead easy to play with HTTP on the REPL (read-eval-print loop i.e. your Python interactive prompt).
Also give these slides a read (and the ones which appear in suggestions if you have some more time). The simplest example of a REST api in action using requests module is:
res = requests.get('https://github.com/timeline.json')
status, headers = res.status_code, res.headers
# print them out to view the headers and the HTTP response status code
# Also, inspect the object attributes to find out what more details you can get from the response object
i am trying to create a library management system which is supposed to be used to store/keep infp for the library and the library members( book title, author, name and picture for borrower and other stuffs). The app has 6 buttons, delete, save, add,previsous,next, and upload( for upload ...