Create a new music project. Click the GarageBand icon and select "File > New" from the menu bar if the "New Project" window doesn't appear automatically.
Plug a MIDI keyboard into your computer if you have one available. You can purchase a MIDI keyboard inexpensively and hook it up to any USB port using a USB-to-MIDI converter cable. Your MIDI keyboard will allow you to record note sequences directly into the Garage Band, using the various instrument settings provided by the program.
Enter a title for your song on the "New Project" window and choose a tempo, or speed. For a techno song, you will want to work with a tempo between 130 and 150 beats per minute. Click "OK" when you finish. Your new project window will appear.
Create an audio track. This will serve as the first layer of your song and will contain your drums and percussion. To create a new track, click the "+" button in the lower left corner of your window and select "Real Instrument Track" from the list that appears. Your track will appear at the top of your mixer.
Add percussion to your beat. Click the "Loop Browser" icon, which looks like an eye and appears beside the "+" button, and click the "All Drums" button. You will then see a list of pre-recorded percussion samples. Click a loop to hear what it sounds like, and select a techno-sounding recording. For example, all of the "Club Dance Beat" loops work very well. When you find a loop that you like, drag it onto your blank track using your mouse.
Create a second track for your bass. Click the "+" button and select "Real Instrument Track" if you want to use a pre-recorded bass loop, or select "Software Instrument Track" if you want to record your own bass line.
Choose an electronic bass loop from the Loop Browser if you do not wish to create your own bass line. If you do wish to create your own bass line, choose a bass setting from the "Track Info" column on the left side of your screen, preferably "Trance Bass" or "Deep Round Synth Bass," and record a bass line by pressing the "Record" button and playing notes on your MIDI keyboard.
Create a third track and add a melody hook. If you wish to use pre-recorded samples, click the Loop Browser and select the "Synths" button. Choose a synth lead from the list. If you wish to record your own melody line, select an instrument from the "Synth Leads" list in your "Track Info" column and record a sequence of notes.
Create additional tracks for sound effects, synth pads or any other layers that you would like to add to your techno beat.
Mix your tracks. Adjust the "Volume" fader on each track until each layer of music blends smoothly into the mix. Additionally, you may want to use the "Pan" dials to move different tracks between the left and right channels, which keeps your song from sounding too centralized. For example, you can move your sound effects 32 percent to the left, and your synth pads 16 percent to the right. Just make sure to always keep your main drum and bass tracks in the center of the mix.
Click "Track" on the menu bar and select "Show Master Track" from the drop-down menu.
Select "Dance" from the "Track Info" column and choose a dance mix from the list that appears. This will adjust your frequencies to give your song more of a natural techno sound. Try a variety of different options, such as "Rave," "Club Chaos" and "Dance Basic," and decide which filter gives you the best overall mix.
Save your project. Click "File" on the menu bar and select "Save."