Mixing is a basic set of skills that separates amateur DJs from the professionals.  Amateur DJs usually just blend music, fading one song in as they fade one song out.  Professional and skilled DJs (like DJ Rock My World team members) mix music, matching beats, tempos, pitches and well as adding their own finesse to a custom mix.  Beat matching, (a technique many amateur DJ’s don’t have) is a method of overlapping tracks so you can have 2 tracks playing in sync with each other.  This type of mixing keeps the energy on the dance floor constant and keeps guests engaged.  In addition to beat matching your DJ may resample, or loop beats and add in effects while mixing.  The result is that everyone has a great time on the dance floor.