If you ever get the opportunity to help in the judges room, be it a scribe or simply staging quilts, it will be an eye opening experience for you. If you really want to know how to win, take the opportunity to volunteer at a show and ask to help in the judges room. You will learn a LOT! Also, enter shows that give you judges comments. It is an invaluable resource to let you know where you need to improve. And don't be afraid to get those comments because they are always worded to mix in compliments along with the critique. Judge comments, probably more than anything will help you to know where you need improvement.
So much depends on the type of show and the judges. Large international shows like Houston, AQS quilt weeks, Road To California, MQX etc are highly competitive. It is a major accomplishment just to get juried into these shows. Some of them are so difficult to get into, it is like winning a ribbon to just be a finalist. At least to me.
The BOS grand prize can reach $10,000 in some of these shows so the competition is stiff. Quilters from around the world enter but you will often see the same names appearing in the top winners circles. Anyone who is an AQS member will recognize the winners in the magazine as it publishes the pictures and names from one venue to the next. It is in these shows that binding can be the difference between winning and not. In fact the competition has gotten so insane many show quilters don't think a regular binding can win any more so many finishing edges are embellished with piping (up to triple pipes!!), beading, unique and unusual variations on prairie points and so much more. The heavy hitters are constantly coming up with finishing techniques to make their quilts stand out from the rest. If it isn't done impeccably well with absolutely no mistakes the quilt won't win. And just because it is fancy and complicated doesn't mean it makes it to the winners circle. Often, something not so fancy is selected because it is done as close to perfect as possible. But finishing edges (binding etc) are just one stage of many in the process of elimination. The first stage is initial visual impact. The judges go through this phase so quickly that any quilt with intricate details in the binding or a perfect finished edge won't even get looked at as the initial visual impact has already eliminated their quilt. All entries have already gone through one round of elimination by the time the judge starts examining the details of the quilt such as binding, construction, chopped points etc. And make no mistake, the judges are going through 100s of quilts in only a few hours but once they get to the detailed inspection they are looking at stitches with a magnifying glass!
Common criteria in these types of shows are use of color, complexity of design, workmanship, stitch length (which must be uniform in both hand and machine quilting), in the case of machine quilted quilts stitch tension, quilting motifs compliment the piecing, quilting density is uniform throughout the quilt (no large areas left unquilted or super dense quilting mixed with really open quilting), no loose threads or compromised seams. Is the quilt free of pet hair, dirt and stains? I once read an article by a quilt judge who was astounded by the number of quilts submitted that had pet hair on them or were dirty.
Smaller, local shows are much less stringent and Peoples choice awards are the least stringent of all. I have seen poorly constructed quilts take peoples choice awards because they make such a great visual impact, or the viewers realize the amount of work in the quilt so even if it isn't perfect they cast their vote because it has such great initial visual impact and a large percentage of viewers realize how much work is involved.
Fairs can also vary so vastly from venue to venue. It all depends on the judges. Many fairs do not use certified quilt judges some of the judges at smaller county fairs are the same judges that are tasting home canned goods and judging other crafts like painting, knitting, etc. They may have absolutely no knowledge of quilting at all. They just give it a cursory look to ensure it is constructed well and is pretty to look at.
This brings up the caliber of judges used at different venues. Again, smaller venues may not be able to afford a certified quilt judge. Many call in quilters who have won at other events or professional longarmers and some even use "guest" judges that again, have basically no quilting expertise at all.
Then it comes down to subjective vs objective. Judging is supposed to be objective. The judge has a list of criteria to rate the quilt but it is impossible for any human being not to let their own hidden bias or subjectivity come into play. If a judge loathes the color orange with all their fiber and being they are more likely to not award as many points to a quilt that is predominantly orange. They may not even realize they are penalizing it because it is orange. This is just one of many reasons why one quilt may not do anything at one show and take major ribbons at another.
Seeing your quilt hanging in a show is super fun to many of us. If it has a ribbon on it when you get there, there is nothing quite like the feeling of accomplishment and happiness it gives you. I get that rush even if it is a quilt I longarmed for someone else and my name doesn't appear anywhere. Yes some have had bad experiences. I have had nothing but good. Yes there are times I could not figure for the life of me why one quilt won a ribbon and another in the same category did not but that won't stop me from participating and entering quilt shows. My best advice to you is to do the very best you can and enter shows where you will get either judges comments or a score sheet so you know where you need to improve and know where you are on solid ground.