Basics are the most important things to consider. No ejection pin marks , mold lines and seams. Second is paint. No runs, dust, and no orange peel. Once you get those two down pat. You can consider adding details. Any details added need to be down flawlessly and in scale. Otherwise don't bother to add it as it will detract from the model. Look at the rules for box stock for any contest you may want to enter. Great way to get the basics down pat.