Once you have imported photos into Lightroom for mobile (or taken some using the Lightroom camera), it helps to identify promising ones or favorites, so you can easily return to them for improvements in the editing part of the app. When viewing a single image, tap the menu in the upper left to choose different ways to work with your images. Choose Rate & Review to add flags or ratings. There are controls for this below the full-screen image, or you can access star ratings by swiping vertically on the left side of the screen, and flags by using the same motion on the right side of the screen. This can be very handy when quickly reviewing full-screen images. 

Swipe on left side to apply ratings; Swipe on right side to apply flags

This tip originally published in Seán Duggan’s Lightroom Tips & Tricks column in Issue 51 of Lightroom Magazine.