The way the parts are installed is going to vary with the type of plane you are building, but I will attempt an answer. Assuming you are building an average 40 sized glow-powered plane...

Attach the engine to the engine mount with bolts and nuts. Attach the engine mount to the plane with bolts too.

Attach the servos to a tray or wood beams inside the plane with small wood screws and grommets.

Wrap the receiver and battery pack in foam rubber and mount them inside with rubber bands or velcro. Make sure they won't move around while the plane is flying.

Check all the bolts/nuts/screws and connections before your first flight and after every 2 or 3 flights to make sure they are still tight. This will help, but there is no way to reduce the chance completely to zero. That's just the nature of this hobby! Good luck!