I go by them goon rules:
If you can't beat 'em then you pop 'em
You can't man 'em then you mop 'em
You can't stand 'em then you drop 'em
“I go by them goon rules” means some version of “I’m willing to fight dirty”
Lil Wayne is making a joke — the 3 Goon Rules are all the same: if you can’t best someone physically, you should shoot him
This is similar to saying “The 3 rules of real estate valuation are location, location, location”