Any ideas how I can fix or minamize this effect?

Get a Dubro E/Z connector if you don't already have one. If you do, then just adjust it to the left till it taxis correctly.

Look at your front wheel. You will notice that the pushrod connects to an arm which is attached the landing gear. There should be a screw in the arm that tightens on the landing gear post. Loosen the screw and turn your wheel to the left a very little bit, then tighten back down. Might take a try or two but you should be able to adjust it so it will taxi straight.

Use a little left rudder... ?

See advice above, sounds like maybe your nosewheel wire has slipped in the control arm. If you haven't already, try adjusting it so that it dead centered, then mark and file a flat spot on the landing gear wire where the set screw tightens down to keep it from slipping.

One thing the others missed was to check how loose the trailing (wing) wheels are on the axles. If one side is tight and has more rolling resistance than the other side, it will cause it to pull to one side also.

Happy landings (and take-offs)