Just trying to start

This year I’m really trying to take life in general more seriously and one thing that crossed my mind to start doing is couponing. My gf is an expert on department store sales but I’m wanting to get more into general purchases and the like. What are some good apps (iOS) and techniques to get the best possible deals?

Purchases would be groceries, household goods (moving soon) and electronics, namely accessories and games. About the only thing I do now even loosely related would be Dosh which has been a bit underwhelming. Anything helps and thanks in advance!