Purchase audio production software or download one of the free music production/beat-making programs, such as Acid Xpress or MU LAB (links provided in the resources section), if you don't already have one of these programs installed.
Review applicable user manuals. If you have never created a beat before, or have never used the audio production software, review the user manual to learn how to use the software to create beats. Programs like Acid Xpress allow you to create beats by arranging loops of different sounds together. Other programs, like FL Studio, provide a step sequencer, which gives you the ability to arrange different loops and sounds as well.
Familiarize yourself with the functions of the software. Locate the volume controls, special effects, tempo monitor, and find the loops and sounds that you will use to put your beat together. Software such as FL Studio and Reason come with a full library of different loops and sounds that you can use to create your beat.
Determine the tempo of your beat. Good rap beats typically have tempos that vary between 85--120 beats per minute (bpm). Most audio production software will have a method of displaying your current tempo and will allow you to modify the tempo as necessary.
Choose a hard-hitting kick or bass drum. The drum is the heartbeat of the rap beat. Choose one that is hard and heavy. Some rap beats are also bass heavy, so consider that as well when selecting your drum.
Select a snare drum and high hat. Be sure that the snares and high hats you choose compliment the kick drum with rhythm and flow naturally together.
Add a melody. Whether an intricate melody, simple piano key notes, or synthesizer strings, be sure to make sure that the melody is catchy, sounds natural and is on key. Experiment with the different sounds and loops. Software such as FL Studio and Reason come with a library of different loops and sounds you can use to create your beat. Search through the library of sounds until you locate the ones you want to use for your beat. You can add more sounds and effects as you go along.
Add in special effects and sounds. This can be good as a finishing touch, but it's not necessary if you feel that the melody in place is complete as is.
Master your rap beat. Adjust the audio levels of each sound used in your beat until a clean, professional sound quality is achieved. You can even add effects such as reverb and delay. Once mastered, your rap beat is complete.