Adjust the velocity. When a beat is first programmed into a drum sequencing program, such as Cubase SX, the hits will all be set with a velocity level of 100. This can be an issue since human drummers almost never hit the drums at exactly the same intensity level throughout an entire song. Use the built in drum editor to make minor adjustments in the velocity for each hit.
Randomize the timing. If a drum beat is looped to an average song length, between three and five minutes, you might start to notice the timing is too perfect. No matter how professional or perfect a real drummer is, the fact they are human will allow for slight variations in timing. To correct this, select the drum track and choose "Track Parameters" from the "Inspector." In the drop-down menu, select "Random." Rest assured, this will not make the drumming sound sloppy, but it will allow for slight variations in the drum track that may not be very noticeable at first, but will definitely add more of a human feel.
Adjust the compression. After humanizing the timing and the velocity, you may still find the actual sound of the drums is too mechanical. Luckily, Cubase gives you a wide range of compression options to help the drums sound more acoustic. A good drum sound is entirely subjective of course, so tweak the compression levels until the signals are boosting where you want them to. You can also try a distortion plug-in to give the samples a bit more bite.
Try different drum samples. If the compression options just aren't doing it for you, there are a wide variety of plug-ins and drum samples that can be ordered or purchased online. Many of these sample sets, such as the "Toontrack: Drum Kit" from Hell EZK, are actual samples from hits on high-quality drum sets recorded with high-quality microphones. Adding this to your drum sequencing program will give you realistic sounds to work with.