Here is a pictorial of how to stitch a feathered heart. I have taken several longarm quilting classes from people like Dawn Cavanaugh, Deloa Jones and Angela Waters. They are very helpful in learning to quilt feathers! I also recommend a sketchbook and/or a whiteboard so you can doodle and build your muscle memory for this design.
Start with your foundation or spine…in this case it is a heart. Then make a “bubble” on the inside peak. (I am showing the steps on a whiteboard, you can see it stitched at the end.) You will stitch four sections: inside right, outside right, inside left and outside left.
Then start the feathers along the inside. It really doesn’t matter which side you start with! Remember you are making question marks, or half-heart shapes. Do not come into the spine at a 90 degree angle, think about merging onto a freeway…you come in almost parallel. You are stitching from the top to the bottom.
Before you start back up the outside, make an extra bubble or two at the bottom. This fills the space without leaving a gap from the end of the last feather loop. Stitch from the bottom to the top with the same question mark/half-heart shape.
You will have more loops on the outside! it can be tricky to come around the curve at the top, just keep making the loops, and think about extending them up as you curve around the top of the heart. Think of an imaginary line through the center of the heart so you can stop without crowding the other side.
Use another extra bubble at the bottom as you stitch back up the outside. Your last loop at the top will just meet the previous feather and give it a kiss! And here is the fabric and thread version: It takes practice to master feathers. Doodle first, then grab some fabric for practice on the machine. When you feel comfortable with the design, transfer the process to a quilt. Each one will look better than the last!