How do I compensate in cura for thinner filament?
In cura (if you are not in the quick print mode) you can dine the diameter of your filament. Setting the filament diameter to a smaller value will give you more plastic coming out of the nozzle. You can also set the flow percentage to more than 100%

You should also try to use a skirt. Some nozzles need some time until the flow is like it should be.

Another reason for this might be that the distance between bed and nozzle is too high. Try to level your bed so that the distance is less than before.

If all this doesn't work then it will at lest give you new ideas of where to look.

Best luck!