Assuming you have checked those points outlined by the other posters, caliper clearance adjustment and bedded in pads, then you could try pumping the lever a dozen times, and keep it squeezed at the last pump, then bung a tie-wrap around the lever and grip without letting go. Leave it overnight and see if you get any improvement. The minute air bubbles in the fluid are compressed and eventually find their way to the reservoir. This is about the only way I can get a decent pedal on my GL1500 rear brake but I hang a big weight on the foot brake lever overnight.
Ian