Make sure you blead it with the heater on full, keep gently squeezing the pipes, with the coolant cap off, run it, cycle between idle and 2500 rpm, top up as required, ensure the heaters are on hot and running, when it blows hot, and no more air comes out, its done.
Another handy tip is to raise the front of the car as high as possible on stands or a ramp, unscrew the coolant bottle, and move it forwards as far as possible, helps get the air out.