position the radio so that it will not get crushed in the event of a crash

keep servo leads as short as possible to minimize voltage drops, and allow delivery of maximum power to the servos to do their job

route antennae as far away as practically possible from the battery, engine, servos, and leads, and metal surfaces

also route antennae so that it can be seen from almost every attitude of the helicopter, my choice immediately down from radio tray and midway between skids and heli frame

i have always used the antennae that comes with the radio set

i believe the roll, pitch, and cyclic servos receive the most opposing forces, the tail rotor servo a close second, and the throttle servo.....just make sure there's no slop

wrap airborne batteries in lots of foam, protects your battery connections from vibrating loose

make battery leads as short as possible for minimum voltage drop, maximum efficiency