Still got poor printing quality after calibrating my Anycubic Predator I've got an Anycubic Predator (aka Anycubic D). I followed the official instructions and leveled my printer. 

The first annoying problem I ran into is that after the auto-leveling, the level test printing shows that the printer wasn't leveled at all. I tried about 4-5 times, and finally leveled the printer (I thought I just got lucky).

The second problem that isn't solved is that the prints I get are of poor quality. Shown in figure 1 and figure 2. The cube should be 20x20x20&nbsp;mm, but what I got here is 19.6(x) x 20.4(y) x 20.5(z)&nbsp;mm.


Figure 1 - X-Y (side) view of calibration square


Figure 2 - Z (top) view of calibration square

Does anyone have any idea about how to improve the printer's printing quality? Thanks in advance.
A few tenths of a millimeter are pretty common for 3D printed parts; these are related to the printer hardware. These inaccuracies can be exaggerated by over- or under-extrusion; e.g. if too much filament is extruded, it increases the outer dimensions (and decreases the inner dimensions of holes).

The images show some signs of over-extrusion, maybe a little too hot also.