How to solve problem of sublimation transfer paper---ghosting and gassing out

All forms of apparel decoration present challenges that must be overcome; it’s simply a natural part of the learning process. You didn’t jump in the driver’s seat of a car and instantly start driving. It took training, time, patience — and probably a lot of close calls — before you became proficient behind the wheel. The same can be said about decoration production; you learn with experience.
Sublimation requires a tight marriage between the transfer paper and the blank product during pressing. If the paper shifts or is not firmly planted against the substrate, it will result in ghosting or gassing out

Ghosting causes a blurry image, typically characterized by a shadow effect along or outside of the edges. Gassing out results in a “burst” of ink outside of the image area. 
The key here is a tight fit between the transfer paper and substrate. Use heat-resistant tape to secure the transfer to the product and don’t tape across the image area, as this can damage the image quality. In addition, use only a minimal amount of tape, as you will need to easily and quickly remove the transfer after pressing. 
When sublimating apparel, you can use “repositionable” spray adhesive instead of tape. Apply a light mist on the image side of the transfer paper from about 10 inches away. Do not spray the shirt. Then press the transfer paper onto the product. If you position it incorrectly, you can lift and reposition it. 
Regardless of how you adhere the transfer paper to the product, it’s important that it doesn’t slide along the substrate’s surface during removal. This may spread sublimation dye into unwanted areas and cause ghosting. Ideally, with hard substrates, the transfer will be lifted off the surface quickly and cleanly. With apparel, it may work better to grab one end of the paper and pull it away slowly, while firmly holding down the garment.