Concentration is something that really helps us focus our attention to a given task. With proper concentration, a lot can be accomplished. I know I personally have a lot of attention problems, often finding myself scatterbrained with too many thoughts racing through my mind at once.
This kanji compound is made up of (集), which means to gather or collect, and then the second character (中) can mean middle (of something) or inside (something). So 集中 (shuuchuu) means you collect all your (thoughts) inside one place to focus.
S-H-U-U-C-H-U-U. Dat concentration.