Consider this simple flower shape. When creating applique pieces, there's a huge advantage to using a fusible that doesn't need to be washed away. The fusible is the white you see. The fusible has been cut as per the pattern sheet - that is, it's the true actual size of the applique piece. It's ironed onto the fabric and then the fabric is cut around the fusible shape with a quarter inch seam allowance. It's this allowance that provides us with the lovely edge we want in our pieces.
When I talk about fusible, I'm pretty much always referring to Floriani Stitch N Wash Fusible. This is my preferred fusible product. It doesn't need to be removed at any stage and after applique, it doesn't bulk out your applique and the quilt can be washed and handled as usual. I'm not associated with Floriani and I don't even get a discount on their products, I have simply found this to be the best fusible for applique so far. I also have trouble finding it outside of the US, so check with your local quilt store and get your hands on as much as you can afford. It can be really irritating to stall a project whilst hunting it down. There may be other products that work just as well as Stitch N Wash, but my location means that I simply don't get access to the large array available to so many North American quilters. I suggest you experiment with as many fusibles as you can to find one that works for you.
When you cut your fusible shape out with the seam allowance, respect the shape of the applique motif. You'll notice I cut my seam allowance with gentle curves to follow the fusible.With the shape plus seam allowance cut out of the fabric, dab the sides with glue. This is to hold everything into position until you're ready to sew( by machine or hand) your applique into it's position. I often use Elmer's Glue in Disappearing Purple. I find that it doesn't gum up my machine or cause any stitching problems. It also washes away later. There was some talk a few years ago that this glue was so good because it was essentially a starch.. and then it was discovered that it actually wasn't a starch product at all and some quilters went off it. Personally I don't care that it's not a starch, it works fine for applique and washes out easily. If you're one of those quilters who doesn't wash her applique, don't worry about it because you won't end up with a stiff cardboard applique shape anyhow.
Once you've glued the seam allowance, snip carefully around the fusible shape. Don't snip right up to the fusible white shape or the cut marks will show on the right side. This takes practice and a sharp pair or narrow scissors.
When I reach tip points that are curved, I neatly pleat the seam allowance as tightly as possible all the way around.
This means that curved points will always look fuller on the wrong side than other parts of the turn edge. After you've created a few, you'll pick up a technique that works for you. I find that pulling the pleats down towards the fusible as tightly as possible and then holding them down until the glue fastens (about a minute) works for me.
This is where I ended up using this shape. It's from a block in my quilt design Secret Garden.
Not bad for a simple applique shape, eh?