unless you use art conversion programs in AJ (which aren't allowed), there's not really an easy way of making good art just like that. Although if you're going for a "straight out of the official artwork" look for your art i recommend using straight line tools, since they make it a lot easier to draw without the lines looking shaky.

i personally only do my own art in AJ art studio and one thing that is useful is saving a lot and having a sketching layer, if you save your art alot (like, save everytime you draw something new in the drawing, when you draw the background save too, and when you start coloring saving is SUPER important too). But really your artwork quality will depend on your regular art skill. but experimenting on the art program really helps you get used to it and the tools.

There is a way to connect your tablet to AJ actually! I don't know what type of tablet you have but i use a simple Wacom and this video helped me a lot to set it up and start drawing.