First up, hook your camera up to your computer via cable. Then, EOS Utility > Camera settings/Remote Shooting.
A panel should pop up that looks similar/like this.
Here, you can control your camera's shutter speed, aperture, and ISO depending on what shooting mode your camera is on (e.g. manual, aperture priority, filming, etc). For instance, if I wanted to change the shutter speed, I would simply click on that box and scroll to the desired speed.
If you want a live view of what your camera is picking up, then hit "Live View Shoot", which brings up this window.
EASY, YUH???? Of course, not the most practical option when you're shooting outside your house, but there's also various phone apps that also lets you control your camera via phone when you're out and about. (This is what happens when you're too cheap to buy a camera remote)
How many of you Canon DSLR owners knew about this?