Pattern Training is solving hordes of basic chess positions (2-move and three-move mates, to be exact) as fast as you can. This type of puzzle-solving will train your eye to recognize mating patterns with certain combinations of pieces.
One of the best books to train this method with has to be "Chess: 5334 Problems, Combinations, and Games" by Laszlo Polgar, father of the Famous Polgar sisters Zsuzsa, Zsófi, and Judit. Start by doing one or two pages a day and increase your solving as much as possible, hopefully getting up to 6 or 7 pages in a day, without too much fatigue. As you progress, you will see that you begin to have 'ah-hah!' moments when you begin to recognize patterns from previous diagrammes already solved.
That is a sure indicator that you are progressing in your tactical, mate-solving training.