When you enter be sure you read the criteria carefully and enter it into the proper division or group.
It is unfortunate that judges let their personal opinions overshadow their unbiased judging but that is the chance one takes. Try to find out what the judging criteria is and how it is judged - elimination system or point system. If more weight is given to the quilting then that is what will get the most attention.
Overall you should: good piecing that is accurate. Long seams should be straight and not wiggly. Binding should be full and straight with small stitches on the back and consistently well mitred corners. Watch to make sure the quilt is square and not wider at the bottom than the top. You can check this by laying out the quilt and bring bottom edge to center and see if it is the same.
For me color is a personal choice by the quilter even tho I might not like the color choises. However, the placement of the color is important to emphasise the patchwork or applique pattern and bring some unity to the overall appearance.
Quilting: Machine should be even and consistent with no knocks or eyelashes on the back. Hand quilting should be even and not necessarily fine fine stitches. They should be even and penetrate evenly on the back. I don't believe they should be the same length on the back as the front. However, some judges want to see that.
So bottom line is to read rules carefully. Try to find out who the judges are. If you don't understand something or disagree with the comments then contact the show chair and ask for clarification.
Some groups want few comments while others want if possible to have very clear and detailed comments. It depends on the number of quilts entered if this can be accomplished.
If the show is being judged by a National Quilting Assn Certified Judge you should be assured they he or she will judge fairly and without prejudice.