Top of print is usually messed up

[printbus]

After calibrating the extruder, I'd probably increase the amount of infill. Am I correct that the ring part is OK? Bridging gaps appears to be a problem, and increasing the infill will provide more support to help with it. What are the dimensions of the parts, and what material are you using? The parts aren't all that big, and PLA might require a print cooling fan to ensure the first solid top layer is ready to support the weight of the next one without sagging much. It could also be there are tweaks to be made to the nozzle temperature (try cooler?) and the print speed being applied to bridges. I see an attempt at two solid layers. After other problems are worked out, adding a third layer would likely help provide a flatter top layer.

DISCLAIMER: I'm fairly new at this myself, so factor that into the value of my input.