What exactly do you want to improve? The pillars are small and PETG is stingy stuff. I can not really see the sides of the pillars that clearly.. The top of the part looks to be under extruded, there should not be able to see the threads below when looking through the cracks between threads. Of course I can not see all that well but to me there looks to be too much open space between your threads on the top layer. We also don't know what your infill percentage is or your number of walls. Are the pillars strong, can you easily snap them off? You are not going to get a nice pretty print with PETG unless it is a simple shape without small islands that require lots of moves over open air and retraction.. It can be done, but there will always be cleanup.. Also if you can post the STL file so we can import it and take a look at it, would be helpful.