The th at the end of a word is softer than the th that begins a word. Tip: You should be able to see the edge of your tongue following the edge of your upper teeth when you pronounce th.

health                                                         earth                                                          fourth
[hell/th]                                                         [‘r/th]                                                           [fo’r/th]

 

 
month
[muh/n/th]