When you make the sound dʒ, your tongue should briefly touch the top of your mouth, the same as when you make the sound of "d" as in "dog." When you make the sound ʒ, your tongue should not touch the top of your mouth. Both sounds are made by pushing air between the lower teeth and the roof of the mouth, but dʒ begins with a brief "d" sound, and ʒ does not.
The two sounds are similar, but the initial "d" in dʒ makes it a sharper sound. You can only make this sound for a brief moment, because of the initial "d." By contrast, the sound ʒ can be continued for a long time, like an "s" or "sh" sound.
As you probably know, in English, the dʒ sound is usually represented with the letter "j." It sounds like the beginning of "jump," "jar," "jam." Sometimes it's also represented by the letter "g," as in "giraffe" (or your example, "danger").