>To the original poster. It is difficult to provide a fool-proof
>recipe, but keep asking questions and you will improve.

The nearest you can get to a foolproof method is to attempt to visualise 
where the ground current is going to attempt to flow between sections of the 
circuit, and work the grounding so that these do not result in ground bounce 
where it will result in a signal appearing that will inject itself into the 
signal path. 

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