1. Use a releaser
I’ve probably made up that word, but what I mean by that is white fat, ie: veg fat or petal base. Run it over your letter of choice before you cut it out will help it to release the paste way easier.
2. Roll it thinly
It being Flower paste! (Gum paste) It really is the best paste to use for cut-out lettering, Rolling it thinly ensures easy release.
3. Cut strips
Cutting strips of paste that is letter height will ensure you will only cut out the letters you need
4. Clean it up
Running your finger over the back of the letter will remove the feathery edges of the letters and make it a clean cut.
5. Release it.
Use a soft paintbrush at the edges to push out the letters, alternately you can use a pin or a craft knife. if none of these methods work for you then get some sugarpaste and press it onto the letter and it will pull the shape out for you.
Thwacking it on the table will inevitably just result in having to cut out more as your letters fly across the room.
6. re-shape it
Put your letter back into shape as it will have certainly wriggled a little when you get it out of the cutter.