Why can't you recognize that you are in the best SAP ABAP Forum SDN. There is no other forum best than SDN. Once just go thru the forums, you will find answers to each and every question.
Hope this helps you.
The SDN forums are great to learn a lot about ABAP and proper techniques. You can find plenty of forums on specific function modules and processes.
The SAP help guide can give you some insight as well. If you have an issue with a keyword or want to learn more press F1 once youve clicked the word and SAP will display a dictionary with information about the word you selected.
Another tool I found useful to access many links was to simply use google. Type whatever it is you want to do and end it with in SAP. Such as delete leading zeros in SAP. This brought up several links through SDN, also SAP toolbox, and links to the SAP dictionary. There are plenty of sources to learn from you just have to go look.