Don't expect to be instantly good. It takes a lot of time, a lot of patients, and determination.
It took me around a year to get to where I am today with scripting.
Here's how I learned:
1. Thought of something small to do(eventually get bigger) like making a /send(/givecash) cmd
2. Went on SA:MP Forums(
http://forum.sa-mp.com/) and searched for a script that did it
3. Read it, and tried to figure out how it worked. If I wasn't sure of something I looked it up on the wiki(
http://wiki.sa-mp.com/wiki/Main_Page)
4. Then I tried to customize it into my own script
Eventually after practicing it just became second nature to me.
Good luck!