(1) set a timer for some specific time (say 5-10 minutes to start, could be more once you get experienced; it's important to use the timer so you don't need to think about when to stop.)
(2) meditate by closing eyes, focusing on the breath, relaxing, for a short time. (practice this by itself first if you are starting out) eyes closed is important because the point is to get your brain producing alpha waves.
(3) focus on some object (could be a thing in the your environment, could be something you visualize) and whenever your mind wanders from the object you put your attention on the object and tell yourself "that is interesting but this is more interesting". it does not matter if you are eyes open or closed at this point because the concentration state involves the brain producing beta waves.