For a quick patch on the fly, apply some Tenacious Tape. Never pull the feathers out—always push the feathers back in. Pulling the feathers out will pull more feathers out. If you are looking for a long-term solution, you will most likely need a baffle repair. While a baffle repair is challenging, it can bring new life to your jacket.
I used Stormsure TUFF Tape on a ripped waterproof jacket. It is clear, self adhesive, and a little bit stretchy too, which is great for the ripped elbow. Each time I bend my arm it puts extra strain on other tape (which I tried unsuccessfully earlier) but TUFF tape has that extra bit of stretch. It has been through the washing machine 3 or 4 times and is still in great shape keeping out the rain. I ordered it online and it came in the mail real quickly.
I bought from Stormsure TUFF Tape