The short version
The safest defense tips are simple: keep cash back for protection, inspect the base before you leave it, and do not chase another player's pet if your own setup becomes exposed. A defense plan reduces avoidable risk; it cannot make the base impossible to raid.
Build a Base and Steal links economy and risk more tightly than a normal tycoon. The same cash that can roll another pet may also be the buffer you need before protecting what you already own, while leaving to steal exposes your own setup. That makes defense a spending decision and a movement decision—not just a building layout.