Solufleece looks like thin fabric and is also washed out in water and Aquabond has a sticky side so fabrics and threads can be positioned on it and then covered with thin film before being sewn onto.
Vanishing Muslin can be sewn onto then dissolved with a hot iron although this does not tend to be used much these days.
Probably the most important thing to remember is that the threads must all touch otherwise when the film is dissolved the threads won't hold together.
Some books that deal with dissolvable work include Fragile Fabrics Jan Beaney and Jean Littlejohn, Dissolvable Delights Maggie Grey and Stitch Dissolve Distort, Valerie Campbell-Harding and Maggie Grey.
Some examples shown below.
Leaf worked on Romeo
Worked on Romeo with the addition of man made cords and knotted cords.
A grid made using threads onto Aquabond
Two pieces of fabric joined using Romeo to stitch onto.
Making Small Christmas crackers
You can also make lacy edges for scarves and will show these in the next post.