Always be ready to change your stance as the situation demands.
Crouching down using the icon in the bottom left-hand corner of the screen will take you out of sight from an enemy. You'll move more slowly around the room as well while in this position. And you'll also move more quietly.
If you want to stay undetected, look out for the objects highlighted with orange lines. When you get close to these pieces of scenery a new Cover button will become available. Tap it to move snugly into position.
You can then peer around the sides of cover areas by tapping left or right.
If the Cover Transfer icon appears on the screen, you can tap on it to dive into the next safe zone.
You can always swap between firearms during play by pulling down on the bar at the top right-hand corner of the screen.
Take manual shots at the enemy, and only switch to auto-targeting if the alarm's raised.
Give the enemy the silent treatment whenever you can.
Green arrows on the radar represent enemies who haven't been alerted to your presence - red enemies are on the look out for you.
Look out for bottles you see lying around the place since some of these contain alcohol which will restore your health once drunk. If you swallow this stuff at 100% health, you'll get a health boost all the way up to 200 hit points.