I've looked everywhere for an old show book or something so that I can tell you exactly what is required for a competition show quilt. But I can't find one, so I am going to give you the basics by memory.
The size of a competition quilt can be up to but not more than 24" per side. Everything should be in scale. For instance, a 24 inch quilt would be fine if made from 1-2" blocks, but you could not do four 12 " blocks. Generally, even a 4" block is considered too big. You should be able to take a photo, and not be able to tell the difference between a full size quilt, and a miniature quilt by looking at the photo.
For instance, look at this wholecloth quilt;
( I borrowed this image from Mariya's site when I found that the link didn't take me directly to this photo. The link DOES take you to photos of many of her wonderful quilts)
It is very small, I think around 9" square, maybe less.
Mariya is a very talented miniature quilt maker, and she makes awesome full size quilts to!
I found a few links that have free patterns for miniature quilts. This writer did all of the work to find the links, so I want to make sure you see her blog! HEART AND HANDS
Carol's miniature paper piecing book is out of print, but maybe you can try the library, or the used books on Amazon. CAROL DOAK MINIATURES
This is a nice company with small quilt patterns. It would be a good place to start if you wanted to try making a miniature quilt. These are tissue paper foundations.
A VERY SPECIAL COLLECTION - LITTLE BITS
I found them at Paducah. They have a nice Carolina Lily quilt, and a diamond shape log cabin star quilt.
For the more adventurous of you, try books by SALLY COLLINS This talented quilter makes miniatures without using foundations. If you want to learn how to do precise piecing without doing paper pieceing, this is your teacher. She makes intricate miniatures, but she also make larger quilts with miniature blocks.
STITCHED RAW EDGE APPLIQUE was what Pat Holly used to make her award winning miniature HIMALAYAN GARDEN
There are many ways to come at miniature quiltmaking. I'm not an expert by any means, but maybe while I am sharing with you, I will learn something myself.