Hi, I can't stress enough how important it is to get the basics down. Learning if/else, understanding the basic skeleton of a script, logic, and knowing how to properly use an onLoop is very important. The basics are used in every script so you will need to learn those. I suggest Code Academy as it really helps to get the basics down. At first it will seem confusing and difficult, but it gets easier with practice.
Head First Java is also a good book to get the basics down, specifically the first few chapters. If you're sole purpose is to only write scripts for runescape, then just get the basics down and do Code Academy. The book is also useful if you want more in sight.
Then I suggest copy and pasting some sample codes from here and start with a basic woodcutter. Try to figure out how to interact with objects like the tree and banker. Figure out how to walk, etc.
Here was my story to becoming a script writer
http://osbot.org/forum/topic/95239-becoming-a-script-writer/page-1
Here is an example of a basic chopper I made along time ago explaining the basics.
http://pastebin.com/ZN54LfHq
Feel free to copy and paste that and edit it.
Please don't try to start by coding complex stuff that you don't understand. It is very annoying when I see people who can't code a simple woodcutter try and coding more complex things. Take baby steps and get the basics down. Goodluck and if you have any questions, don't be afraid to ask P.S. Stay away from the chatbox with your questions, you will most likely be trolled. @Tom will roast you about any questions you ask.