To beat the Jelly Queen, you have to spread more jelly on the board than she can. Your jelly is pink and the Jelly Queen’s jelly is green.
Match areas in the Jelly so they overlap with areas that don't, for your Jelly area to grow.
If you create special booster candies, you will stun the Jelly Queen and get an extra turn. If you create three special candies in a row you can do a power move, which creates an explosion. If placed right it will spread more of your jelly.
Tip: Avoid matches that could work in favor of the Jelly Queen!