I don’t use an app, but one of the things that I’ve found helpful are mindfulness recordings on itunes. I have recommended 10, 20, and 30 minute Yoga Nidra recordings to my clients. Yoga Nidra is one of many forms of guided relaxation, where you relax and draw your awareness to different body parts one at a time. Very relaxing. Very easy for the beginner who isn’t ready to do a “clear the mind” type of meditation.