Probably even more important than learning how to write software is learning how to debug it!
(the same could be said of hardware design)

Key to being able to fix any problem is being able to clearly describe its symptoms - "not getting proper result" is no help to anyone.

You need to:
1. carefully consider what you think should happen;
2. carefully examine what actually does happen;
3. try to account for the discrepancy.

This is the basis of The Scientific Method.

See: http://www.8052.com/forum/read.phtml?id=118587

Update - see also: http://www.8052.com/faqs.phtml?FAQ=120313