Visit online loop providers (see the Resources section for links) and download loops that complement your desired style of music. For example, if you want to mix techno music, select an array of synthesizer loops, sound effects and electronic drum sounds. If you want to mix rock music, select loops that use traditional analogue instruments and distorted guitars. Download enough loops to fill the different parts of a song (melody, bass, percussion, effects), and pay close attention to the tempo (speed). Unless you possess software that allows you to speed up or slow down individual tracks, you will want to stick with loops that use the same speed. You can usually find this information on the download page.
Open a digital audio workstation with a multi-track mixing interface. In plain English, this refers to any music editing software that uses "tracks," or layers, arranged as long horizontal bars for placing the different parts of a song. Such programs include Pro Tools, Audition, Logic, ACID, Reason, Cubase, and free programs like GarageBand for the Mac, QTractor, Audacity and LMMS (see Resources).
Drag all of the loops you want to use onto the software window. If you drag the files onto the blank space of the window, they should appear in their own, newly-created tracks. You can place multiple loops on the same track, but for mixing purpose, try to designate a different track for each different kind of loop. For example, you can place two lead guitar loops on the same track, but do not place a drum loop and a guitar loop on the same track, as these sounds will require different mixer settings.
Arrange your loops as they should appear on the timeline, which typically appears above the first track, along the top of the software window. If you place a loop on the far left end of the window on a track, it will play at the beginning. If you place two loops in the same position on the timeline (for example, if you place a live drum loop and a keyboard loop both at the "0" mark on the timeline, on their respective tracks), the loops will play simultaneously. To repeat a loop, click the right edge with your mouse and drag it across the time line, repeating as many times as needed.
Adjust the volume on each track to begin mixing your loops. When you have all of your loops positioned in their appropriate spots, you can begin the mixing procedure. Balance your levels by lowering the volume of any track that dominates the mix, and by raising the volume of any track where your sounds fade into the background. Your volume fader for each track should appear in the left column of your work window.
Pan your loops. "Panning" refers to the process of transferring specific tracks into the left and right channels (speakers), creating a more realistic-sounding mix. For example, while you must always keep your bass and kick drum in the center, you can move your guitars toward the right in the stereo mix while moving your keyboards to the left, so that each part shares the mix without blending into every other track. Your "Pan" option should appear as a dial or a slider in the left column of each track, alongside the volume. If your software uses a round dial, turn it clockwise with your mouse to move a track toward the right channel in the mix, or move it counterclockwise to move it toward the left channel.
Add effects to your loops. If your "Effects" options do not appear directly on the tracks themselves, double-click one of your tracks to see expanded options. Among these options, you should find filters such as "Echo," "Chorus," "Reverb," "Distortion," "Phaser," "Compression," "Pitch" and other effects. Apply appropriate effects to any track to enhance the sound. For example, if your keyboards lack personality, you can add an echo to create a more electronic, techno-oriented atmosphere. If your guitars lack depth, you can add distortion to enhance the aggression. Experiment with different effects.