With regard to the europiccola, Im sure you are doing this already, but make sure you let a little steam out when it reaches temperature. This supposedly lets out any trapped air in the boiler and lets it reach the right pressure. Also, I find it helps to run water through the group to warm it up and flush it out before pulling the shot. I also think it helps to let the machine get good and hot before pulling, rather than going as soon as the heating light goes out. I seem to get better shots if I do, but it could just be correlation rather than causation.
Sandancer
With regard to the europiccola, Im sure you are doing this already, but make sure you let a little steam out when it reaches temperature. This supposedly lets out any trapped air in the boiler and lets it reach the right pressure. Also, I find it helps to run water through the group to warm it up and flush it out before pulling the shot. I also think it helps to let the machine get good and hot before pulling, rather than going as soon as the heating light goes out. I seem to get better shots if I do, but it could just be correlation rather than causation.