Setting SMART goals

I have recently been reading about goal-setting, time management and decision making and there was something interesting that I came across on Mindtools about setting smart goals. Now haven't we all heard of that before but they had an interesting twist to it -

S-Specific
M-Measurable
A-Attainable
R-Relevant
T-Time-bound

Quite 'smart', isn't it?
Also realized that Pareto's principle (80:20 rule) does influence my daily productivity significantly! What exactly is the 80:20 rule as applied here? - 80% of unfocused effort produces only 20% of the results desired.