To get your toes warm to this practice, the following attachment is a glossary of potential embers symbols I found in Peggy Vickers 1977 book, The Home Book of Fortune Telling. Author Vickers said this list of meanings was compiled from the testimony of seers experienced in the art, and who had come to identify these symbols and their meanings over the years:
You may well see many images in the embers which aren’t on the list, which are specific to you, and which have meaning only for you. This is where you’ll have to rely on your own intuition and gut-hunches as to whether it’s an omen or just another ember burning on the hearth. You may get to a point where you can throw the above glossary on the fire and go with your own instincts. But it will equip you with a beginning visual vocabulary which will help you in your first efforts at embers-divining. Be on the look-out also for Runes, Ogham, and Adinkra symbols in the embers, as well as images from the Tarot, LeNormand, Sibilla, and Kipper decks—if the Spirits know you’re familiar with these symbol-systems, They may choose to communicate that way.