Scripts are made in Java, so knowing Java is a MUST. A really great tutorial for the basics: http://www.youtube.com/watch?v=3u1fu6f8Hto
After you watch that, try messing around and doing different things with what you learned. Get a feel for the language and how it works, maybe even look up more advanced tutorials! Once you know the basics of the language THEN you could move onto scripting, even though making complicated scripts requires an advanced knowledge. Here's a tutorial for beginning scripting for OSBot (assuming you know Java): http://www.youtube.com/watch?v=Mdil7v1J5es