Freeze the code plan, before you leave

I have been trying to recap all that thought process that I originally had when I was thinking for a solution to some problem. Practising to freeze your plan originally is a better approach. Leaving a code snippet in middle is a lethal task, getting out immediately for another task is easy but as you proceed further, frustration of what has not been done or chances of forgetting the original ideas/striking points are proportional to the time you proceed forward.
Why not :
a) Write down the original plan on paper
b) Going through the flow manually
c) Looking for possible tools to be used and code patterns
d) Then after freezing we just need to write the source code.
Some straight forward points but easily forgotten.